Without a doubt, industry has created an amazing variety of molecules and materials that go into the products that are a large part of our modern way of life. For a majority of the chemicals and compounds outside of the pharmaceutical industry, we have a limited amount of information upon which to make reasonable decisions about their toxicity to humans or the environment, their degradability (biological or otherwise), our ability to recycle or reuse them, or their renewability.
Society is heavily dependent on the products of the chemical industry; however, most of us know very little about where the basic building blocks come from, at what social and environmental cost, and if there are any elements facing critical supply constraints. For many elements that are of critical importance, like those used in catalysis, electronics and energy production, we are taking a large amount of mass, concentrating the desired elements and dispersing these same elements into a form that is sometimes difficult to recover and reuse.
This talk will set the context for the problem, discuss several compelling examples where key material life cycles need to be closed, and discuss a way forward.

Energy, water use, and environmental impacts are among the first topics that researchers consider in sustainable materials development. However, minimizing the negative human health impacts of materials and their production processes is just as critical to ensuring the safety of current and future generations.
Spurred by recent industry actions, such as internal retailer policies (e.g. chemical "red lists") and green building rating systems like Leadership in Energy and Environmental Design (LEED) that are incorporating more stringent requirements around materials impacts, manufacturers are increasingly expected to account for both the environmental and human health aspects of their products. Because of this, they are looking for ways to redesign or reformulate their products to meet the needs of the changing marketplace. In some cases, manufacturers have difficulty finding substitutions for chemical and material ingredients deemed unsuitable due to their negative effects.
This situation presents both new considerations for researchers creating novel materials destined for the marketplace, as well as new opportunities for research into safer material chemistries and processing methods.
This talk will make a case for human health considerations being an integral, yet oft-overlooked, component of sustainable materials development. It will highlight important governmental policies and regulations in this arena, recent industry actions impacting environmental and human health considerations of materials, and present new opportunities for research.

There has been a recent move by scientists and engineers in the United States to tailor some of their work for developing countries and areas. The idea is that engineering can help to meet some of the basic needs of impoverished people, raise their standard of living, and create more sustainable communities. Past projects have included attempts to provide off-the-grid energy, clean water, and wastewater treatment and/or disposal. The interest in this topic can be seen in the variety of efforts to outline engineering strategies for the Millennium Development Goals and the fact that it is increasingly difficult to find a major university that does not have an active Engineers without Borders program.
Unfortunately the history of the modern world&’s attempts to address impoverished areas through technology transfer is riddled with failures. Sometimes the technologies sit unused weeks after they are introduced. Sometimes the technologies disrupt the social fabric of the community. Problems like these arise not because the motives of the engineers were necessarily bad, but because their training is mainly in technical areas and only a small part of the overall problem is technical in nature. There are rare occasions when technologies mesh with the infrastructure, social frameworks, and needs of the community to enable positive lasting change. These successes come only when the designers involved understand the people they are working with. And even then a fair amount of luck is needed.
This presentation will cover the basic lessons developed for a training program designed to help engineers and scientists interested in addressing the problems of t\he developing world. The two day workshop has already been held at Georgia Tech and the University of the Western Cape in South Africa and by the time of the fall MRS meeting it will have been held at Concordia in Montreal as well as Arizona State University. The workshop does not give participants everything they need to know to be able to engage in development work, but helps them to avoid some of the common pitfalls that doom many projects at the earliest stages.
Most significantly the workshop focuses on the importance of working to understand the relationship between technology, people, and the environment and provides tools to begin to learn more about their interactions. It argues that the key to any successful project is successful engagement. Outsiders will never be able to understand the context of the situation well enough to create a successful design. Opening up ways of communicating with the community are crucial even as early as the first step of defining what problem might be useful addressed. The workshop illustrates the dangers of not listening and provides techniques for engineers and scientists to better listen to the people they want to help and observe the environment in which they will work.

Proponents for sustainable alternative lighting and display options advocate for organic light-emitting diodes, particularly polymer light-emitting diodes (PLEDs) whose color range extends the entire visible spectrum, because of their potential low-cost fabrication, low operating voltage, and low power consumption. In this work, a materials life-cycle analysis was completed for three alternative device configurations to the conventional bottom-emitting PLED device structure - inverted bottom-emitting, conventional top-emitting and inverted top-emitting - due to their potential to increase device operational lifetime (inverted) and light out-coupling efficiency (top-emitting). The study was completed in terms of the following metrics: materials cost, projected total life cost savings, life-cycle power cost, and operating energy consumption per unit area. We find that glass, indium tin oxide (ITO), and conjugated polymer active-layer materials are the main contributors to materials cost for the conventional bottom-emitting device, accounting for 70 %, 12 %, and 14 % of the materials cost, respectively. This is a result of the large glass layer thickness (greater than1000 µm) compared to other device layers (less than 142 nm) and the high cost to fabricate both ITO and the active-layer materials. Approaches to increase the total life cost savings are: implementation of device designs that utilize thinner glass substrates that can be re-used following a device lift-off process; elimination of indium tin oxide; and increasing device operating lifetime and efficiency. We will show that the conventional bottom-emitting device has the lowest total life cost savings, approximately 3 times that of its top-emitting counterpart, while the inverted top-emitting device has the lowest life-cycle power cost and operating energy consumption per unit area due to its approximately 1.5 times longer operational lifetime and its factor of 2 reduction in power consumption. In addition, electromagnetic simulations of light extraction efficiency and the percentage of light energy trapped or absorbed in each layer of the devices will be presented and considered alongside the other metrics to select the optimal device architecture in terms of efficiency, cost and environmental factors.

The availability of drinking water and water reuse for agriculture or industrial purposes has been increasingly facilitated by membrane technology. Well-established processes like reverse osmosis dominates the market for water desalination. Other emerging processes are being implemented with the development of membranes with a diverse set of properties. Examples are nanofiltration for partial desalination of seawater for agriculture, forward osmosis for hybrid water reuse systems, microbial fuel cell and pressure-retarded osmosis for water-energy recovery. Our group has been dedicated to the synthesis of new polymers, their functionalization and morphology control aiming at the application to water-based separations. We focus on the development of porous membranes, which depending on hydrophobicity can be applied membrane distillation (MD) and ultrafiltration, as well as support for multilayer nanofiltration or forward osmosis membranes. We have been working for instance with fluorinated polyoxadiazoles and polytriazoles for MD. Analogous polymers with different chemical functionalizations have been used to manufacture solvent resistant membranes (hollow fiber and flat-sheet) for ultrafiltration and as support for forward osmosis. Besides chemical functionality, morphology control is a challenging task. Most of the available membranes have a broad range of pore size distribution. We have been exploring special techniques based on block copolymers to enable the manufacture of membranes with exceptional high and regular porosity. Recent advances and strategies for membrane manufacture for water-based separations will be summarized.

A paradigm shift towards renewable fuels like biodiesel comes with the adverse aspect of excess raw glycerol byproduct, fermentation of which to 1,3 propanediol provides a sustainable recourse to waste utilization. However, the downstream enrichment of such polar organics, typically produced in dilute mixtures, constitutes a major process efficiency bottleneck. Although membrane separation processes offer cheap and energy efficient alternatives of upgrading the concentration, high water affinity of 1,3 propanediol compounds the difficulty in pervaporative enrichment prompting the need to develop novel materials. The synthesis of a novel hydrophobic imidazolium ionic liquid salt monomer and its polymerization and copolymerization is presented. The monomer chemically anchors a hydrophobic high boiling solvent via a Menshutkin like pathway. The polymers are characterized by spectroscopy, thermal analysis, thin film water contact angle and mass uptake. A plug membrane is fabricated from these polymers and evaluated for batch pervaporation with a separation factor of ~ 100. These values are bettered only by high boiling hydrophobic cyanoborate ionic liquid based supported liquid membranes. Incorporation of a small molar percentage of Divinyl benzene and butyl acrylate causes a reduction in separation performance but is seen to maintain mechanical integrity for a longer period of time, thus allowing for structural membrane engineering and industrial scale up.

Our rapidly developing modern society challenges to scientific and engineering organizations in that many of the currently used technologies and prospective engineering innovations need to be directed in a more sustainable way. Therefore, materials science and sustainable engineering will continue to have important roles in five key thematic areas such as energy, transportation, housing, materials resources and health [1]. In parallel with the experimental efforts, computer-aided materials design is also an important factor in the fabrication of novel materials, to be applied in driving engineering innovations and urgent technological needs for achieving a sustainable society. The recent advent of metal-organic framework materials (MOFs), as new functional adsorbents has attracted the attention due to scientific interest in the creation of unprecedented regular nano-sized spaces and in the finding of novel phenomena, as well as commercial interest in their application for storage and separation. For MOFs the structural versatility of molecular chemistry has allowed the rational design and assembly of materials having novel topologies and exceptional host-guest properties that are important for urgent sustainable applications. Due to the regularity of MOF structures, in a computer simulation we are easily able to build structural models of MOFs that are very helpful to find new materials with desired characteristics.
The aim of this study is detailed theoretical analysis the adsorption of targeted molecules into selected nanoporous materials in order to accelerate the realization of novel materials, hand-in-hand with experiment. Here, our recent achievements have been reported. The high sorption ability for acetylene on specific MOF material was determined [2], using both different experimental measurements and first-principles calculations which ascribe to the double hydrogen bond support between the acidic acetylene proton and its acceptor basic site on the channel surface. The absorption of several chiral sulfoxides, which constitute an important class of biologically active compounds and therapeutic drugs, into the homochiral porous coordination polymer has been also investigated [3]. In collaboration with experimentalists the specific nanoporous material that selectively adsorbs CO with adaptable pores has been studied using first-principles calculations. The high selectivity of CO has been achieved from a mixture with nitrogen by both the local interaction between CO and accessible open metal sites and the modification of nanopore size [4].
REFERENCES
[1] D. Apelian, MRS Bulletin2012, 37, 318.
[2] R. Matsuda et al. Nature 436 (2005) 238.
[3] D. N. Dybtsev et al. Chem.-Euro. J. 16 (2010) 10348.
[4] H. Sato et al. Science 343 (2014) 167.

Water scarcity affects one in three people globally. Membranes are a key technology for water sustainability, for example wastewater reclamation and reuse. They also use less energy and no added chemicals, which makes their use more “green” compared to distillation and other separation methods. But current commercial membranes are susceptible to fouling, which manifests as a loss in permeability due to macromolecular adhesion on the membrane surface. Fouling lowers productivity and increases energy consumption and cost. We need membrane materials that offer excellent fouling resistance, along with high flux and selectivity. Here we report a new class of membrane materials using self-assembling zwitterion-containing polymers. Zwitterionic groups strongly resist biomacromolecular fouling due to their high affinity with water, which makes them favorable for membrane applications. Zwitterions are known to self-assemble into channel-type clusters of 0.6-2 nm in size. We have shown that within certain composition ranges, random copolymers of zwitterionic and hydrophobic monomers self-assemble to form bicontinuous networks of nanochannels. We have synthesized such copolymers and formed thin film composite membranes by coating them onto commercial ultrafiltration membrane supports. These membranes exhibit permeabilities as high as 21 L/m².h.bar, which can be further improved by better membrane manufacturing and processing methods. Based on the rejection of anionic dyes of varying sizes, they show size-based selectivity with a size cut-off around 1 nm. This pore size closely matches the size of the zwitterionic nanochannels, measured to be ~1.1-1.4 nm in diameter by transmission electron microscopy (TEM). We have also demonstrated the excellent fouling resistance performance of these membranes in parallel to a commercial membrane of comparable pore size. We expect these membranes to be promising candidates for various membrane and sustainable water applications.

Nanofiltration technology is being investigated as a cost-e#64256;ective and environmentally acceptable mechanism of sustaining industrial and public water systems. Nanofiber membranes are part of the family of filtration devices being used to remove inorganics and organics from water systems. This study investigates the use of the natural material, Opuntia ficus-indica (Ofi) cactus mucilage, as a tool for nanofiber membrane filtration. Mucilage is a natural, non-toxic, bio-compatible, biodegradable, inexpensive and abundant material. Mucilage is a clear colorless substance comprised of proteins, mono-saccharides, and polysaccharides. It also contains organic species which give it the capacity to interact with metals, cations and biological substances promoting flocculation for removing arsenic, bacteria, E. coli, and other particulates from drinking water. This natural material has the potential to be used as a sustainable method for water filtration and contaminant sensing. Therefore, mucilage nanofiber membranes were electrospun with volume ratios of polyvinyl alcohol (PVA) and polystyrene (PS) to mucilage comparing the interaction of non-polar solvents. Atomic Fluorescence Spectrometry (AFS) from PSAnalytical was used to evaluate electrospun nanofiber membranes made from volume ratios ranging from 30:70 to 70:30 of mucilage: polyvinyl alcohol, mucilage: polystyrene-D-limonene, and mucilage: polystyrene-toluene in different proportions. The mucilage nanofiber membranes were used as filtration devices for 50 ppb arsenic solutions. Arsenic, being a toxic substance, acts as a deadly poison in water systems and has plagued societal preservation for centuries. The total arsenic content in the samples were measured before and after treatment. Comparative tests were also performed using 1) coated and non-coated GVWP 0.22 µm and 0.45 µm filters from Millipore and 2) columnar flow through Pasteur glass pipets filled with 0.5 g of pre-washed sand from Fisher Scientific and 0.01 g of mucilage nanofibers. Results show mucilage: polystyrene nanofiber membrane filters were capable of removing arsenic from test solutions, in terms of the percentage of arsenic removed. These data elucidate that mucilage nanofiber membranes have the potential to serve as the basis for the next generation of economically sustainable filtration devices that make use of a natural non-toxic material for sustainable water systems.

Civilization on our planet took a sharp turn about 250 years ago, at the beginning of the industrial revolution, and has accelerated on that highway ever since. Arguably, its impact on humankind is equivalent to that of the invention of fire. The enormous consequences of industrial activity, positive and negative, could not have been anticipated then, but the bottom line today is that
per capita global consumption of energy is higher than ever, and demand for materials (relative to the year 1900) has increased by factors of 3 to 6000, depending on the element. Total population as well as those segments of the population doing the consuming, is also increasing. Now we speak (informally, thus far) of the Anthropocene, the first geological epoch in which human activity is deemed to have had an effect on the Earth&’s ecosystem. For how much longer can economic growth and demand for goods be sustained, and can the same human ingenuity that started the industrial revolution mitigate its effects?
In this talk I will address the meaning and definition of sustainable development, and explore the space at its intersection with materials science. Every human endeavor should be informed by sustainable development, because none of our material resources are in#64257;nite and only a few sources of energy are sustainable. The most common definition of sustainable development comes from the 1987 Brundtland report, “Our Common Future”, and states that “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” However, this is not a scientific definition, and essentially refers to economic development. Further, it requires that we know, or at least accurately estimate, what the needs of future generations will be. The immediate and direct connections between sustainable development and materials science include ef#64257;cient use of materials, materials life cycle assessment, replacement materials, energy-related materials, and water puri#64257;cation. I will highlight what MRS as a scientific society has been doing in the field of sustainable development, and suggest what future materials scientists should know about this field. From MRS&’s activities in sustainable development thus far, we have learned that there is nothing we do as humans to ensure our survival (food, water, materials, shelter, economy, health) that lies outside of its boundaries.

The National Science Foundation has a crosscutting initiative, Science, Engineering and Education for Sustainability, which supports research through a portfolio of programs. One of these programs, Sustainable Chemistry, Engineering and Materials (SusChEM), is particularly relevant to the materials community. This talk will provide an overview of sustainability and its significance to society and materials research. Topics covered in SusChEM and other NSF programs will be described in detail. These include, but are not limited to, utilization of earth-abundant elements; materials for food, water and energy sustainability; and designing products and devices for zero-waste.

Public outreach is often framed as a process of developing lesson plans with an aim of convincing the public to believe a series of facts and/or accept a specific viewpoint. These one-way patterns of communication, however, frequently fall short in at least two important ways. First, the public has many sources of information so getting the attention of a number of people is difficult. And second, the organizations that put together such programs are missing a major source of information that could help them to achieve their goals. Over the past several years museum professionals with the Nanoscale Informal Science Education Network (NISE Net) and scholars at Arizona State University&’s Center for Nanotechnology in Society have been developing techniques that go beyond this “linear model.” These techniques enable two way conversations in which members of the public learn about scientific achievements in a specific area and then build their own ideas of what they think a better future would like with them. What we have found is that the visitors to science museums in the United States are not only able to participate in constructive conversations, but that they are hungry for them. This talk will outline some of the lessons learned through this partnership and offer suggestions for how they can be implemented in other spheres.

Corporations are the greatest threat to the sustainability of our planet, and yet also promise to be the most effective means of resolving sustainability challenges. What shapes whether they do harm or do good? In this presentation, I focus on the role of a firm's stakeholders in influencing the firm's behaviors. In particular, I outline the role of firm-stakeholder relations in the business case for corporate social responsiblity, and I discuss several studies I've conducted that shed light on the limits of the business case for conditioning firms to engage in socially responsiblity practices.

In the last decades many efforts have been directed towards the development of efficient energy conversion systems using renewable energy resources. In the scenario, particular for automotive applications, the development of low temperature fuel cells plays a critical role towards the development of a sustainable hydrogen-based-economy. Alkaline fuel cells (AFCs) were the first low temperature fuel cells developed in the 1960s and mainly used for space program applications. Afterwards, mostly due to the electrolyte deterioration when in contact with CO₂, the interest in these systems has been shelved for many years. In parallel, the higher efficiencies and the advantage of using a polymer electrolyte membrane have driven the main research efforts towards the development of polymer electrolyte fuel cells (PEFCs). The main performance drops in PEFCs are caused by the cathodic electrode where the oxygen reduction reaction (ORR) takes place. For the development of competitive PEFCs the discovery of durable and cost-effective catalysts for the ORR is one of the most urgent requirements. State-of-the-art PEFC cathodes are based on Pt nanoparticles supported on high surface area carbons.¹ Despite the relatively good performance as cathode catalyst, Pt-supported on carbon suffers from corrosion stability, particularly due to carbon oxidation. Therefore, a growing interest is raising toward alternative, more stable support materials. In the present contribution alternative oxide-based supports have been investigated^2-5 and an insight into Pt/oxide novel catalysts will be presented.
In the last decade the development of alkaline conductive membrane has raised again R&D interest towards AFCs. Compared to PEFCs, AFCs make use of an electrolyte medium which is less corrosive with respect to a wider range of compounds, thus significantly broadening the range of possible stable and inexpensive electrode materials. Due to the above mentioned reasons, a broad range of materials has been investigated in recent years as alternative catalysts to noble metals. Particularly, perovskite oxides have shown the potentials of high electrocatalytic activity towards ORR in alkaline media. In this contribution the performance of different perovskites as ORR catalysts will be presented, unraveling the oxygen reduction mechanism for this novel class of materials.^6,7
The authors gratefully acknowledge: Swiss National Science Foundation (Ambizione Program), Swiss Competence Center for Energy Research (SCCER) Heat & Electricity Storage, and Umicore GmbH.
[1] E. Fabbri et al. ChemCatChem 6 (2014)1410-1418.
[2] A. Rabis et al. Phys. Chem.C 118 (2014) 11292-11302.
[3] E. Fabbri et al. Phys.Chem.Chem.Phys. (2014) DOI:10.1039/C4CP00238E.
[4] E. Fabbri et al. Chimia 68 (2014) 217-220.
[5] T. Binninger et al. J. Electrochem. Soc. 161 (2014) H121-H128.
[6] E. Fabbri et al. ChemElectroChem 1 (2014) 338-342.
[7] E. Fabbri et al. ACS Catalysis 4 (2014) 1061-1070.

Sustainable electricity generation technologies are highly variable, and energy storage has an important role in integrating them into the grid at large scale. Building this energy storage capacity has an energy cost, as with any manufacturing process. However, different energy storage technologies have different energy costs for manufacturing the same kilowatt-hour of storage capacity. Net energy analysis, a type of life cycle analysis, systematically examines the life-cycle energy costs of technologies such as energy storage. In this work, we apply net energy analysis to evaluate a regenerative hydrogen fuel cell (RHFC) as an energy storage system. To compare RHFC's to other storage technologies, we use the energy stored on invested (ESOI) ratio: the ratio of energy stored in the device over its lifetime to the energy required to build and operate the device. A device with a higher ESOI ratio provides the same service while consuming less energy during manufacture and operation, leaving the difference available for other productive uses. We present a model to determine the ESOI ratio of a RHFC system as a function of system properties such as storage capacity and fuel cell efficiency.
The ESOI ratio of our hypothetical RHFC system is similar to that of the best battery technology (Li-ion, ESOI = 10; Energy Env. Sci., 2013, 6, 1083), though still lower than those of pumped hydro (ESOI = 240) and compressed air (ESOI = 210). A sensitivity analysis highlights priorities for catalysis research in order to optimize the system's net energy performance: The most important technology advance for increasing the system's ESOI ratio is increasing the fuel cell lifetime to at least 20,000 h, and the electrolyzer lifetime to at least 50,000 h. In contrast, the ESOI ratio is only modestly sensitive to the efficiency of the electrolyzer and fuel cell, and to the embodied energy requirements for manufacturing these components. The system's energy-to-power ratio is also an important parameter. Although there is substantial uncertainty in the embodied energy values, uncertainty analysis indicates that on a net energy basis, a RHFC system can be competitive with Li-ion batteries even with higher-than-estimated embodied energy values. Finally, we illustrate the opportunities for further technology development to improve the net energy balance of RHFC's. For instance, in an RHFC system with an extended-life fuel cell (50,000 h) and electrolyzer (150,000 h) and an energy-to-power ratio of 10, the ESOI ratio would approach 80, well above that of any battery technology.

Core-shell ferrite materials can be utilized for thermochemical water-splitting process to achieve relatively stable hydrogen volume generation in multiple thermochemical cycles. Sol-gel derived ferrite nanoparticles can be further utilized for the preparation of core-shell nanoparticle morphologies. During sol-gel synthesis of core-shell morphology achieving monodispersion of ferrite nanoparticles pose significant technical challenge. As ferrite nanoparticles are magnetic by nature, while preparing the dispersion their agglomeration is unavoidable. To address this issue, we attempted to prepare monoparticulate dispersion of ferrite (e.g. NiFe₂O₄) nanoparticles, which were later subjected to in-situ zirconia coating following the sol-gel chemistries. Monoparticulate dispersion of ferrite nanoparticles were investigated in presence of non-ionic and ionic surfactants such as Pluronic P123, sodium dodecyl sulfate (SDS) and cetyltriammonium bromide (CTAB) whereas the effects of these surfactants on particle morphology were studied during controlled hydrolysis and condensation reactions of zirconium isopropoxide with water. The obtained ferrite/zirconia gels were aged and calcined at 600^oC. Transmission electron microscopy (TEM) revealed core-shell nanoparticle morphology whereas x-ray diffraction showed desired phase composition. These core-shell nanoparticles were loaded inside Inconel tubular reactor where multiple water-splitting and regeneration steps were performed at 900^o-1100^oC. These results indicated relatively stable H₂ volume generation during 10 consecutive thermochemical cycles. The thickness and porosity of ZrO₂ shell was found to depend on the type of surfactant used and optimum concentration of the surfactant and reactants employed. H₂ volume generation ability of the monoparticulate core-shell ferrite nanoparticles was further correlated with the thickness and porosity of ZrO₂ shell. Specific surface area (SSA) and porosity of core-shell nanoparticles were analyzed by BET surface area analyzer whereas grain growth was characterized by scanning electron microscopy (SEM) and TEM after thermochemical water-splitting reaction. Characterization of core-shell nanoparticles and the results obtained on H₂ volume generation with core-shell ferrite nanoparticles will be presented.

This talk will provide an overview of recent progress in the development of sustainable photocatalytic materials for solar-driven production of hydrogen from water. The emphasis will be recent realization of disorder-engineered titanium dioxide, starting with an introduction of the electronic band structure resulted from disorder incorporation. The method of making disorder-engineered titanium dioxide nanocrystals will be presented, followed by measurements of their structural, electronic, and optical properties. Photocatalysis experiments based on solar-driven hydrogen production using disorder-engineered titanium dioxide nanocrystals, that can absorb solar energy in both visible and infrared wavelength regions, will be summarized, followed by an analysis of the fundamental physics underlying increased photocatalytic efficiency of disorder-engineered titanium dioxide nanocrystals.

A Redox Flow Battery (RFB) possesses several key advantages that make this technology potentially well suited for large scale energy-storage applications. This is especially true of applications that require high energy-to-power requirements (i.e., multiple-hour discharge times at rated power) since the energy capacity can be increased by simply adding reactant solution without necessarily requiring (or negatively impacting) the power-delivery components. Despite this inherent scaling-factor advantage relative to conventional battery systems, the initial capital cost of flow batteries has been the major barrier to commercialization of RFB technology. Capital-cost targets for grid-scale energy storage are challenging; battery systems for major grid-scale applications must cost less ($/kWh) than those currently used for most portable or transportation applications. One attractive path to cost reduction is the development of RFB cells with substantially higher power densities than conventional RFB cells. United Technologies Research Center (UTRC) has developed and demonstrated high performance flow-battery cell stacks operating in complete Prototype RFB Systems. A summary of these results has been presented previously. Therefore, the focus of this talk will be on new materials that can potentially enable additional RFB-system cost reductions. This includes both advanced cell materials (e.g., electrodes, separators/membranes, bipolar plates) that can further improve the performance RFB cells, as well advanced reactant solutions. Key system-performance indices provide the basis for the formulation of key property requirements for these advanced materials. A brief review of the state-of-the-art of each these major materials will be included, along with their key properties. The major goal of this presentation is to help material developers identify potential opportunities to substantially improve RFB technology.
Acknowledgements
The author would like to thank his multiple colleagues at UTRC who have been an essential part of UTRC&’s advanced flow-battery team.

Sn₂Fe has been regarded as a promising candidate to replace presently dominating graphite anodes due to its low cost, environmental benignity and high theoretical capacity (804 mAh/g)¹. However, the electrochemical reaction mechanism of Sn₂Fe is not fully elucidated yet. It has been widely reported that Li-Sn alloys could be formed during lithiation of Sn₂Fe while Fe being extruded, whereas Fe is difficult to be detected^2,3. But there is a debate for the delithiation process, during which some researchers claimed that the “liberated” Fe particles would remain inert so that Sn₂Fe could not be re-created⁴, while others argued contrarily that Sn₂Fe could be reproduced upon delithiation². To have a comprehensive understanding of the reaction mechanism of this material, pure Sn₂Fe was prepared solvothermally by reducing SnCl₂ and FeCl₃ with NaBH₄; the reaction mechanism during the first two cycles has been thoroughly investigated through a variety of in-situ and ex-situ characterization techniques such as X-ray absorption spectroscopy (XAS), powder X-ray diffraction (XRD), pair-distribution function (PDF) analysis, etc. Our results confirmed that the Li-Sn alloys were formed during the lithiation process, so was the Fe phase; such a reaction is reversible upon delithiation and most of Sn₂Fe could be re-formed (but with a small portion of discrete Fe and Li-Sn alloys being inactive). During this reaction, the formation and dissolution of Fe were successfully identified by a combined analysis of synchrotron-based XRD, XAS and PDF techniques. This research is supported by DOE-EERE-BATT, DE-AC02-05CH11231 under Award Number 6807148, and by NYSERDA.
(1) Zhang, R.; Upreti, S.; Stanley Whittingham, M. Journal of The Electrochemical Society2011, 158, A1498.
(2) Yoon, S.; Lee, J.-M.; Kim, H.; Im, D.; Doo, S.-G.; Sohn, H.-J. Electrochimica Acta2009, 54, 2699.
(3) Chamas, M.; Sougrati, M.-T.; Reibel, C.; Lippens, P.-E. Chemistry of Materials2013, 25, 2410.
(4) Nwokeke, U. G.; Alcántara, R.; Tirado, J. L.; Stoyanova, R.; Yoncheva, M.; Zhecheva, E. Chemistry of Materials2010, 22, 2268.

Platinum-group metals supported and dispersed on highly reducible oxide surfaces are active catalysts for several reactions of industrial interest, including water-gas shift, selective CO oxidation, hydrocarbon reforming, low-temperature hydrogen/methanol oxidation, and oxygen reduction. Due to their high cost, there is an ongoing effort for reducing the amount of precious metal without affecting the device efficiency. In the context of polymer-electrolyte-membrane fuel cell electrodes, ultra-low loading Pt-ceria (CeO₂) systems are investigated as potential candidates for meeting the new national and international targets [1].
Density functional theory calculations are used to rationalise the enhanced reactivity displayed by these Pt-ceria systems and to characterise the active sites of new materials that minimise the Pt load by means of solid solutions. In particular, I will first focus on supported sub-nm Pt clusters and establish the role of cluster morphology in the thermodynamics and kinetics of surface processes relevant for reactivity: cluster mobility, charge transfers at the metal-oxide interface, reverse oxygen spillover, and oxygen vacancy formation [2,3]. I will then present a thermodynamics analysis that predicts the stability of specific Pt²⁺ and Pt⁴⁺ species in realistic reaction conditions, emphasising the key role played by O vacancies, surface steps and solid solutions [4]. The results will be discussed in the context of recent STM images and XPS data. The different reactivity of these sites towards hydrogen and methanol oxidation will be established and rationalised in terms of local electronic and morphological properties.
The calculated results allow for rationalising the available experimental data and identify correlations among the mechanism of reaction, thermodynamic efficiency, and local structure of the active sites, thus shedding light on the origins of the reactivity and stability of novel Pt/CeO2 materials for fuel-cell electrodes.
[1] A. Bruix et al., Angew. Chem. Int. Ed., in press.
[2] P. Ghosh, M. Farnesi Camellone, and S. Fabris, J. Phys. Chem. Letters (2013)
[3] F. R. Negreiros and S. Fabris, submitted (2014)
[4] M. Farnesi Camellone, F. R. Negreiros, and S. Fabris, submitted (2014)

Tungsten Oxide is still considered a promising candidate as photoanode for both, water splitting and CO₂ reduction. However, photocurrent densities obtained up to now are far away from the theoretical values according to its band gap (2.7 eV). The short diffusion length of the charge carriers limits the thickness of the WO₃ films and consequently its light absorbance. In this work, we present high crystal quality WO₃ films deposited by Pulse Laser Deposition (PLD) which reduces bulk recombinations through grain boundaries and increase diffusion lengths. Finally, a Al₂O₃ surface passivation was applied using Atomic Layer Deposition in order to diminish recombination at surface states and also the formation of peroxo-species.

Boron Nitride (BN) nanoparticles were synthesized employing hot filament chemical vapor deposition technique; using borazine as its gas precursor. These samples have been characterized to reveal their morphology, their chemical components, and their structure; using techniques such as the scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) & Fourier transform spectroscopy (FTIR). In previous analysis it has been shown that BN interacts with hydrogen gas, enhancing its electrical resistance. It has been shown that significant amounts of hydrogen gas adsorbed in the BN nanoparticles, making it a suitable material for safe hydrogen storage and transportation applications that can facilitate the utilization of new energy technologies, such as fuel cells. The BN nanoparticles show great cycleability in such the H adsorption-desorption processes without degradation or poisoning.

Carbon dioxide emission from anthropogenic sources is a chief source of greenhouse gas in terrestrial atmosphere. Carbon dioxide is the most abundant byproduct of all respiration, fermentation and combustion processes, leading to a steady increase in concentration by 2.07 ppm every year. Thus, the sensing, capture and storage of carbon dioxide has become crucial to control and consequently reduce the emission of carbon dioxide, to curtail environmental pollution.
Classical approaches towards carbon dioxide capture from concentrated sources usually require two mols of primary or secondary amines to capture one mol of carbon dioxide in the form of ammonium carbamate salts. In the current approach a series of solid-supported tertiary amino alcohol adsorbents are developed for more efficient uni-molecular capture of carbon dioxide. The energy efficient pressure-swing carbon dioxide desorption process also makes these materials more advantageous over the classical adsorbents, which entail thermal regeneration. The application of these tertiary amino alcohols is further extended to develop reusable, inexpensive colorimetric sensors for the facile detection of small amounts of gaseous carbon dioxide. The visible detection range is 2-20%, encompassing the concentrations of carbon dioxide in ambient air or flue gas. These materials have potential use in food, beverage, as well as mining and chemical industries.

As engineers strive to develop a practical and energy-efficient method with high efficacy to separate oil/water mixtures, especially those stabilized by surfactants has proven to be extremely challenging. Here, we describe a powerful yet economic strategy for the synthesis of superhydrophilic and prewetted oleophobic nanofibrous membranes by the facile combination of in situ cross-linked polyethylene glycol diacrylate nanofibers supported on polyacrylonitrile/polyethylene glycol nanofibrous (x-PEGDA@PG NF) membranes. The as-prepared x-PEGDA@PG NF membranes have shown superhydrophilicity with ultralow time of wetting and promising oleophobicity to achieve effective separation for both immiscible oil/water mixtures and oil-in-water microemulsions solely driven by gravity. These new membranes are endowed with good mechanical strength of 14 MPa and very high flux rate of 10,975 L m-2 h-1 with extremely high separation efficiency (residual oil content in filtrate is 26 ppm). More importantly, the membrane exhibits high separation capacity, which can separate 10 L of an oil/water mixture continuously without a decline in flux and excellent antifouling property for long term use. These suggested that this cost-effective membrane could be used as promising materials for treating wastewater produced in industry and daily life, crude oil, especially for high viscosity oil purification.

It is not easy to solve the ongoing issues of worldwide environmental pollution. In both the chemical and petrochemical industries, the nanofiltration of organic solvents may make a significant contribution to improved energy efficiency in the production process. Polymer-based membranes are widely used for gas separation, filtration, desalination of seawater, wastewater treatment, etc. Chemical, petrochemical, energy and environment-related industries, however, strongly require highly durable membranes applicable under extreme conditions, since the present polymeric membranes gradually or sometimes rapidly deteriorate with time due to undesired swelling, clogging, and chemical reactions. In our poster presentation, new porous diamond-like carbon (DLC) membranes will be discussed. The DLC was first prepared by Aisenberg and Chabot by means of an ion-beam deposition technique [1]. At present, a widely used technique for DLC deposition is plasma chemical vapor deposition (CVD) using organic compounds. In the plasma CVD of organic compounds, a highly cross-linked network of sp³ carbons is obtained under certain conditions, resulting in thin carbon films with mechanical stability comparable to that of diamond. DLC has been seemed to be extremely dense and it is used mainly for gas barrier applications. In contrast, recently, we successfully prepared nanoporous DLC membranes which exhibited extremely high permeability to water and organic solvents while maintaining a considerable degree of mechanical strength [2, 3]. We believe that the nanoporous carbon membranes open the way for the water treatment.
[1] S. Aisenberg and R. Chabot: J. Appl. Phys., 42, pp. 2953minus;2958 (1971).
[2] S. Karan, S. Samitsu, X. Peng, K. Kurashima and I. Ichinose: Science, 335, pp. 444minus;447 (2012).
[3] S. Karan, Q. Wang, S. Samitsu, Y. Fujii and I. Ichinose: J. Membr. Sci., 448, pp. 270minus;291 (2013).

As one of the most widely studied hybrid nanostructures, core-shell nanoparticles are attracting more and more attention, since properties arising from either core or shell materials can be quite different. Currently, core-shell nanoparticles have been used for many applications, including catalysis, environmental remediation, information storage, biomedical imaging, and energy harvesting. The aim of this work is to synthesize precisely controlled silica-cobalt (SiO₂-Co) core-shell nanoparticles for catalytic applications. The core material of SiO₂ nanoparticles has been synthesized by the Stöber method. Then, the SiO₂ nanoparticles were subjected to surface modification with 3-aminopropyltrimethoxysilane. The Co shell with controlled thickness was formed by a chemical reduction method. The size and morphology of the SiO₂-Co core-shell nanoparticles have been characterized by the field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The SiO₂-Co core-shell nanoparticle has been used as a catalyst to degrade methyl orange, a common azo dye containing azo functional group (-N=N-). The degradation characteristics and kinetics were investigated by measurement of the absorption of the dye solution with a UV/Vis spectrometer. Kinetic studies revealed that both the surface adsorption and degradation contributed to the absorption spectra. Reductive degradation by the SiO₂-Co core-shell nanoparticle catalyst is a very promising approach to the remediation of azo dye containing waste water due to the fast degradation rate and high degradation efficiency.

Carbide has been considered as important phase in two commercial Fe and Co catalysts for Fisher-Tropsch synthesis (FTS). Iron carbide has known to be more active in FTS than metal iron and dominant phase rather than metallic Fe under FT reaction condition. On the other hand, the cobalt carbide (Co₂C) is not directly involved in FTS. The formation of Co₂C occurs easily under low H₂/CO ratio (< 1) conditions and has been considered rather as a deactivation route of cobalt-based catalyst during FTS. However, the produced Co₂C could be activated to Co_hcp phase in slurry phase by H₂ bubbling at a relatively low temperature of 220 °C. We experimentally demonstrated that the Co_hcp catalyst activated from Co₂C showed higher catalytic activities in slurry phase FTS, compared with Co_fcc reduced from cobalt oxide. In this study, for high catalytic performances in FTS, we reported an optimum procedure for preparing cobalt carbide depending on the process temperature and pressure, and also demonstrated the simple route for the activation of the cobalt carbide. We could clarify the activated condition of Co₂C. Also, we considered the application in regeneration of deactivated cobalt catalyst, using the formation of Co₂C and subsequent hydrogenation. It was confirmed that this carburization-hydrogenation treatment could enhance the catalytic activities of the regenerated Co_hcp in FTS rather than the initial activities of the cobalt catalyst.

The global water poverty crisis is now becoming a problem of serious concern all over the world. To obtain fresh water from seawater, recently a forward osmosis (FO) process has been developed as an attractive alternative to distillation and reverse osmosis. FO uses a 'draw solution' to osmotically pump water molecules out from feed solutions through a semipermeable membrane. Solutes in this draw solution are separated to produce usable water. However, the FO method for practical desalination remains problematic given its drawing system, low drawing power, energy costs, complicated separation, and difficult recovery of the draw solutes. In this study, we present an innovative method based on draw solutes with lower critical solution temperature (LCST) phase separation from water to induce the abrupt change of effective concentrations and osmotic pressure.
Because temperature-sensitive materials show temperature-driven hydrophilic to hydrophobic transition in aqueous condition, corresponding abrupt changes of effective concentration in the solution containing those materials could induce conversion of osmotic flows. Derived from the structure of LCST polymer, we synthesized N-acylated tris(2-aminoethyl)amine (nBu-TAEA). It has low MW (356g/mol) and shows LCST-type phase separation above ~27 Celsius. nBu-TAEA aqueous solution showed clear conversion of osmotic pressure upon low and high temperature. The nBu-TAEA solution could draw fresh water from a seawater (0.6 M NaCl) at the temperature below the phase separation point, and release the drawn fresh water into low-salt water at higher temperatures. Finally, a new desalination system was produced via circulation of the draw solutions between low and high temperature sets allowing direct seawater-drawing, transfer and release of water, and separation and recovery of draw solutes in a simultaneous and continuous manner with high energy efficiency.

Scavenging mechanical energy from the ambient environment has attracted worldwide attention and is also an important way to realize sustainable development since mechanical energy is a zero-carbon emission, and widely available energy source. Among all of the available technologies of mechanical energy harvesting, contact-electrification enabled nanogenerators, i.e. triboelectric nanogenerators (TENGs) emerge as a new energy technology with numerous advantages, including large output power, high efficiency, and easy fabrication with low cost. The basic working principle for TENGs is a combination of contact electrification and electrostatic induction. The contact-mode TENG has been demonstrated to have numerous applications both as a power source and as an active sensor. However, there is still a lack of a systematic theoretical model in this field. Experimentally, it is known that the maximum power on a load as provided by the TENG is a result of matching between the TENG and the load. However, a thorough theoretical understanding about how the structural parameters and operation conditions of a TENG affect the match with the load is still missing, which is critical for designing a compatible TENG for a specific application.
In this work, a comprehensive theoretical model is built for the contact-mode TENG. Utilizing the derived equation, the real-time output characteristics of the TENG are mathematically modelled and the equivalent circuit model of TENG was derived. Then based on the calculation results, we clarified the physics behind the three-working-region behavior and the optimum load resistance. The optimum load resistance is formed because of the impedance match of internal TENG capacitance and load resistance. Finally, the quantitative relationship of the optimum resistance with the parameters of TENG is derived to provide guidance for rational design of TENGs for a specific load. This work is the first in-depth interpretation and analysis of the contact-mode TENG&’s working principle, clearly showing its unique operation characteristics, which will be able to serve as important guidance for rational design of the device structure as a power source in specific applications and self-powered systems. ^[1]
Reference:
1. Simiao Niu, Sihong Wang, Long Lin, Ying Liu, Yu Sheng Zhou, Youfan Hu, and Zhong Lin Wang, Energy & Environmental Science 6 (12), 3576 - 3583.

Salinity-gradient energy is a promising sustainable energy source. Among the technologies using the salinity-gradient energy, reverse electrodialysis (RED) is a very efficient process retrieved from the difference in the salt concentration between seawater and river water, often called a concentrated salt solution and a diluted salt solutions, respectively. The alternating arrangement of sea water and river water, cation- and anion-exchange membranes placed between two electrodes is allowed to generate Donnan potential and finally to pass charge to external loads by the passage of ions through the membranes. In fact, seawater has complicated water chemistry by mono- or multi-valent ions and organics which are huge but has charge. In the phenomena of ion transport through the ionic selective membranes, some multivalent cation such as calcium or magnesium cause some hydroxide precipitation on the surface of cation-exchange membranes and some negatively charged organic substances could be attached onto the surface of anion-exchange membranes. It is called fouling. The fouling makes further fouling phenomena accelerate such as enhanced water dissociation to worse the precipitation of multivalent ions by the fouling of anion-exchange membranes by organic substances. Thus the fouling is significantly interconnected. In this study, we investigated influence on the performance of ion-exchange membranes in a RED system due to foulants dissolved in sea and river water and provided the solving or mitigating methods. To study the effect of fouling when both feed waters are similar with natural conditions, the performance has been evaluated for open circuit voltage (OCV), stack resistance and power density.
ACKNOWLEDGEMENT
This research was financially supported by the New and Renewable Energy of Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean government&’s Ministry of Trade, Industry and Energy (No. 20143030071240).
REFERENCES
1. Vermaas, D. A., Kunteng, D., Saakes, M., Nijmeijer, K., WATER RESEARCH, 2013, 45, 1289.
2. Post, J. W., Hamelers, H.V.M., Buisman, C.J.N., J. Membr. Sci., 2009, 330, 65.

The unique structural architecture of carbon-based nanoporous structures such as activated carbon (AC) has made activated carbon one of the most viable materials to address current environmental challenges. The highly developed porosity, large surface area, tunable surface chemistry, and high degree of surface reactivity make AC the most widely used adsorbent for the removal of wide variety of organic and inorganic pollutants dissolved in aqueous media or from gaseous environments, as well as the use as electrodes in energy related applications. Traditional feedstocks for AC production include, primarily, mineral carbons, and lignocellulosics from biomass and wood. However, any cheap material, with a high carbon content and low mineral content, can be used as a precursor for the production of AC. Agricultural wastes are proving to be promising precursors for the production of ACs mainly due to their availability and low cost.
We present preliminary investigation on utilized chemical activation technique to convert agricultural waste (cocoa and coconut husks) into ultra-high surface area activated carbon suitable for myriads of environmental and energy related applications. Our preliminary investigation of KOH activation of coconut husks biochar already indicates extremely high BET surface area ~ 2900 m²/g. The AC shows potential for an electrode application in supercpacitor.

Oil-water separation is critical for both oil recovery and oil pollution treatment. Conventionally, the oil industry depurates oil and water by centrifuging, which consumes large amounts of energy. A more environment-friendly method is to employ meshes (or membranes) for oil-water separation. Meshes with superhydrophobic surfaces were first introduced. However, since most oils are lighter than water, the separation performance of hydrophobic and oleophilic meshes becomes limited. Recently, underwater superoleophobic meshes were used to achieve low-energy and fast oil-water separation.
Nevertheless, the challenge in scaling up this technology is the fabrication of high flux rate meshes with longer life span and lower cost. The mesh pore size will play an important role on the oil-water separation flux rate. As the superhydrophilic mesh is easily contaminated by the oil which usually has a lower surface tension compared to the water, a proper design for meshes (or membranes) based oil/water system will be needed.
We have successfully fabricated a superhydrophilic nanostructured copper mesh with a contact angle of about 150 degrees through a very simple and rapid chemical etching technique. With this mesh, the underwater superoleophobic behavior has been experimentally observed and oil was separated from water. Theoretical analysis predicts the condition zone for underwater superoleophobic phenomenon, which also agrees with the experiments. Further study is ongoing to investigate how the mesh pore size and roughness affect flux rate, which is critical to improve the mesh performance. A continuous loop will be built and tested under industrial conditions before large-scale application of the proposed meshes. Other practical issues, such as life time, reliability, and cleaning, will be addressed.

Recently, we have extensively studied the photocatalysts (titanium oxide; TiO₂ and zinc oxide; ZnO) nanomaterials (nanoparticles, nanowire etc.) for remediation of organics including oil in water. The photocatalysts are grown using the hydrothermal and sol -gel techniques [1]. It is challenging to control the size and shape and quality of the nanowires, and find effective remediation of organics in the visible light. However, the success of organic remediation by iron and silver doped in ZnO has been shown from our group [2, 3]. We are also growing the graphene doped photocatalyst ZnO nanowires and graphene doped TiO₂ nanoparticles for organic remediation in water similar to graphene-silicon oxide nanoparticles [4]. In the present work, G-TiO2, G-ZnO, G-(ZnO+TiO₂) nanocomposites were synthesized by using hydrothermal techniques and sol-gel techniques. Each synthesized material was characterized using SEM, FTIR and X-Ray Diffraction, techniques. The graphene doped ZnO nanowires shows the better remediation in visible light than graphene -TiO2 based materials. The comparative remediation properties of organics (methyl orange (MO), toluene, naphthalene etc.) with and without presence of surfactant have been studied under visible light.
1. M Ladanov, P Algarin-Amaris, G Matthews, M Ram, S Thomas, A Kumar, Microfluidic hydrothermal growth of ZnO nanowires over high aspect ratio microstructures, Nanotechnology 24 (37), 375301
2. I Udom, MK Ram, EK Stefanakos, AF Hepp, DY Goswami
One dimensional-ZnO nanostructures: Synthesis, properties and environmental Materials Science in Semiconductor Processing applications, 16 (6), 2070-2083.
3. I Udom, Y Zhang, MK Ram, EK Stefanakos, AF Hepp, R Elzein, R Schlaf ...
A simple photolytic reactor employing Ag-doped ZnO nanowires for water purification, ,Thin Solid Films (in press) 2014
4. TE Alam, MK Ram, M Ladanov, F Alvi, A Mujumdar, A Kumar
Synthesis and Characterization of Novel Graphene Silicon Oxide Nanocomposite Material, MRS Proceedings 1400, mrsf11-1400-s08-07

We have developed the method to fabricate the regular free standing b-oriented MFI membrane with the support of polymer. It shows straight b-oriented membrane, and promising for xylene separation.

This work presents a method of treatment in oils based in a filter of metallic iron oxide(III) nanoparticles (Fe₂O₃) functionalized carbon nanotubes (CNTs). These materials have properties allowing their use to dispose compounds of industrial oils (metal-mechanic). The aim of this filtering process is the removal of contaminants from waste oils to avoid damage at environment as ground, flora, fauna and future generations. The characterization of oxide iron nanoparticles functionalized carbon nanotubes was carried out by TEM and Raman spectroscopy, and the results show that there is a covalent functionalization in CNTs. The oils filtered with functionalized CNTs show, in FTIR spectrum, an elimination of different residual compounds that having industrial waste oils.

Membrane distillation (MD) is a thermal desalination technology that uses membranes to create large interfacial areas for vaporization of water from salt solutions. In the MD application, the membrane hydrophobicity is a critical parameter for reducing the wettability of membranes. Increased hydrophobicity should lead to higher liquid entry pressures (LEP) for pores of a given size, and reduced opportunity for liquid breakthrough that would compromise salt rejection in the MD process. Electrospun fiber membranes are considered good candidates for MD membranes due to their combination of high porosity and small pore size. Polyvinylidene fluoride (PVDF) and its copolymers with trifluoroethylene are the most common choices of material for the manufacture of electrospun fiber membranes for membrane distillation, due to their combination of fluorine content and solubility in common solvents. However, PVDF is only sparingly hydrophobic, with an intrinsic contact angle of around 90 degrees. In this work, we fabricate electrospun PVDF fiber membranes with various fiber morphologies, such as beaded fibers, rough fibers, and porous fibers, in order to increase the apparent hydrophobicity of the membranes. The effect of fiber morphology on apparent contact angle, LEP, and MD performance are discussed.

Platinum (Pt) based nanomaterials have been extensively employed in catalytic and electrocatalytic applications, showing excellent performances toward a myriad of reactions. As properties in metal nanomaterials are strongly dependent upon shape, size, morphology, and structure (solid versus hollow interiors), the precise control over any or several of these parameters opens up the possibility to tailor and/or optimize properties for a target application. In this work, we were interested in developing Pt nanomaterials possessing hollow interiors as well as dendritic morphologies, as these features may allow for higher surface to volume ratios when compared to their solid and/or rounded counterparts, which is particularly attractive for catalytic applications. We describe herein the synthesis of Ag-Pt hollow nanodendrites displaying controlled and monodisperse sizes and well-defined morphologies by combining galvanic replacement and precursor reduction reactions. We employed Ag nanospheres as seeds/sacrificial templates, PtCl₆^2- as the Pt precursor, hydroquinone as the reducing agent, PVP as the stabilizer, and water as the solvent. The catalytic performances of the obtained Ag-Pt materials were investigated towards two reactions: i) the 4-nitrophenol reduction by NaBH₄; and ii) the oxidation of volatile organic compounds (benzene, toluene and xylene) by dioxygen. Here, the hollow Ag-Pt nanodendrites were deposited onto commercial SiO₂ through a wet impregnation method, which enabled their uniform dispersion over the support. We believe that the approach described herein can serve as a platform for the synthesis of hollow nanondendrites having a wealth of sizes, compositions, and surface morphologies for applications in catalysis.

Homogeneous catalysis has a huge impact on human&’s daily life and global environmental system. Several weaknesses shared by homogenous catalysts lead to poor sustainability: (1) they are difficult to be isolated from the reaction pot, giving rise to product purification issues, and (2) the aggregation of active sites during reactions impedes their recyclability. Herein, we use metal-organic framework (MOF) materials as a tool to circumvent the sustainability issues of homogenous catalysts. In our system, the homogenous catalyst (guest) is encapsulated in the cavity of the MOF porous material (host), a 3D infinite coordination polymer. The advantages of using MOFs as hosts lie in the diversity of structures and their tunability through the functionalization of the organic linkers, which allows the engineering of the local environment of the cavity. Different guests, such as catalytically active Rh(I) and Ru(III) organometallic compounds, and host materials, such as ZIF-8 and UiO-66, were investigated in our study.

Among several classes of metallic nanomaterials, those displaying hollow interiors as well as sharp tips/branches at their surface, such as hollow nanoflowers, are especially attractive. While hollow interiors provide larger surface-to-volume ratios than their solid counterparts, sharp tips/branches at the surface enable improved performances for catalytic and electrochemical applications due to higher surface areas relative to their rounded counterparts. In this work, we describe a facile strategy for the synthesis Ag-Pd hollow nanoflowers supported on silica (AgPd/SiO₂) displaying monodisperse and controllable sizes, well-defined morphologies, and uniform dispersion over the support. Our approach was based on seed-mediated growth that combined the galvanic replacement reaction between Ag and PdCl₄^2- and the PdCl₄^2- reduction to Pd in the presence of hydroquinone. Also, polyvinylpirrolidone was employed as a stabilizer and water as the solvent. The AgPd/SiO₂ were investigated as catalysts for benzene, toluene and xylene (BTX) oxidation, showing good catalytic activities (product conversion: 94% of benzene, 70% of toluene and 50% of xylene) at relatively low temperatures (300^oC) using O₂ the as oxidant. The results described herein demonstrate the potential of hollow metallic nanomaterials displaying tips/branches at their surface for catalytic applications.

Hetero-nanostructured (HNS) composite semiconductors show unique charge transport characteristic, and may play an important role in addressing the worldwide energy crisis and environmental pollution problems. Besides the material composition, the interface structure of heterojuntions also has a significant effect on the charge transfer and separation, even light absorption performance. However, most of the heterostrutured composite photocatalysts reported so far were prepared by sol-gel or co-precipitated methods and possessed an uncontrolled interface. Herein, we concentrated on the construction of the heterostructured composite photocatalysts with well-defined interfacial structures, which show less interfacial defects and minimized interfacial resistances. Noticeably, for the materials such as Ta₂O₅ or TiO₂, whose precursors have rapid hydrolysis rates, we have developed a synchronous etching-growth process to deliberately regulate their growth. Using this process, we demonstrate here that the NaTaO₃/Ta₂O₅ photocatalysts with a well-defined heterostructured interfacial structure can be steadily available. At the same time, we have also developed a novel and efficient liquid-phase in-situ epitaxial growth strategy for the ingenious fabrication of hetero-nanostructures of Ag₃PO₄ quantum dots on hematite nanotubes (q-Ag₃PO₄@Fe₂O₃ HNSs) with a well-defined heterojunction. In our protocol, the pre-adsorbed phosphate anions as a hardly dissociative form in the surface of α-Fe₂O₃ nanotubes (NTs) ensure the heterogeneous nucleation and in-situ epitaxial growth of Ag₃PO₄ on the external walls of α-Fe₂O₃ nanotubes. Compared with randomly deposited hetero-nanostructures and separated components, the as-obtained HNS photocatalysts with a well-defined interfacial structure can not only accelerate the separation and transfer of photogenerated charges, but also induce the directly interfacial charge transfer, and thus further extend the light absorption range of the heterostructured composites. As a result, both composites exhibited excellent photocatalytic activities either for hydrogen production or for organic pollutant degradation. The in-situ epitaxial growth methods developed here are promising to fabricate heterostructured composite materials with well-defined interfaces, exhibiting potential applications in photocatalysis, solar cell and so on.

Recent concerns over the potential health and environmental consequences of halogenated flame retarding polymers and additives motivates the discovery of new non-halogenated flame retarding materials. We demonstrate the use of multifunctioanal deoxybenzoin-based molecules as non-halogenated flame retardants integrated into polymers. We describe the synthesis of 2,4,4&’,6-tetrahydroxydeoxybenzoin (THDB) as a multifunctional cross-linker in conjunction with bis-epoxydeoxybenzoin epoxide (BEDB), affording new resins that combine excellent physical and mechanical properties with low flammability. Thermogravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC) were used to measure the char residue and heat release capacity of the cured materials, respectively. Resins incorporating THDB exhibited low total heat release (13 kJ/g) and high char yields (34%), as well as good mechanical properties, making them suitable candidates for consideration in high performance adhesive applications. The desirable heat release and char forming properties of these resins are realized without the presence of any conventional flame retardant, such as halogenated structures or inorganic fillers that are commonly used in commercial materials.

In this work, we present a flexible solid supercapacitor fabricated with an automated spray coating system using a nano-composite based current collector structure and electrolyte. Supercapacitors are a promising technology for the storage of electrical energy due to their very high power and energy storage capacity [1]. Supercapacitors also offer longer lifetime, short charging and discharging time and higher number of charge-discharge cycles with respect to the conventional battery technology. The supercapacitor electrodes consist of a conductive current collector and an active material with a high specific surface area [2]. Increasing the contact area between them can reduce the resistance of the current collector and the active layer.
In this research, a network of silver (Ag) nanowires (Sigma-Aldrich-778095) with the length and diameter ~50 mu;m and 120-150 nm respectively is used as a current collector [3]. The ink is prepared using activated carbon particles (Sky Spring Nanomaterials-0530HT) with the average size less than 100 nm and deposited on an ionomer membrane by an automated spray coating system (Sono-Tech ExactaCoat). Consequently, a thin coating of Ag nanowires is directly sprayed on the carbon coated electroactive layer. To further improve the adhesion between the carbon and Ag nanowire layer and to provide polymer backbone to the Ag nanowires, a layer of PEDOT:PSS is deposited on top of the Ag nanowires using the same automated spray coating system. The resulting supercapacitor is degassed for 30 mins to evaporate organic solvents.
The PEDOT:PSS and Ag nanowire based current collector structure has high conductivity, excellent adhesion to the active layer and efficient charge transport for the fabricated supercapacitor. The morphology of the electrodes is studied using a scanning electron microscope (FEI-Dualbeam 235). The cyclic voltammetry (CV) and galvanostatic charge/discharge are performed by potentiostat (PARASTAT 4000). The proposed current collectors indicate a low resistivity. The electrochemical test shows high capacitance (4.8 mF.cm^-2). This fully solid supercapacitor can be used as an energy storage device or a power source for electronic applications.
1. Huang, C., Grant. S, “One-step Spray Processing of High Power All-solid-state Supercapacitors” Scientific Reports 3, Article number 239, 2013
2. H. C Wua, Y. P Lina, E. Leea, W. T. Linb, J. K. Hub, H. C. Chenb, N. L. Wua, “High-performance carbon-based supercapacitors using Al current-collector with conformal carbon coating” , Materials Chemistry and Physics, Volume 117, Issue 1, pp 294-300, 2009.
3. Patel, J., A. Chang, C. Cordoba, B. Kaminska, “Printable Powering Patch for Portable Devices”, IEEE PowerMEMS Conference, Energy Harvesting Devices and Systems, London, UK, 2013.

Microbial fuel cell (MFC) is a bio-electrochemical system that generates power by using different organics as fuels in presence of bacteria, which typically comes from wastewater as the natural source of these microbes. They can be described as bioreactors that operate under anaerobic conditions with the catalytic activity of microorganisms to convert and transform the energy from the chemical bonds of organic compounds into electrical energy. The active bacteria can work inside microbial fuel cells and decompose fuels to generate bioelectricity by organic waste oxidation and renewable biomass. Additionally, microbial fuel cell is an amazing tool that can help the environment by removing waste from water and converting it into useful energy.
The basic structure of the conventional microbial fuel cell is typically composed of an anode and a cathode, separated by a proton exchange membrane (PEM) in a two chambers configuration. Both electrodes, anode and cathode, must be conductive and the anode must be biocompatible with the bacteria introduced into the system to form a biofilm as the biochemical catalyst that will transform waste into useful energy. The liquid organic fuel is introduced into the system and bacteria start to oxidize it and generate protons and electrons. The protons pass to the cathode through the proton exchange membrane and the electrons transferred from the anode to the cathode through an external circuit driving an external load and reducing the electron acceptor at the cathode.
In our case of study, we use a micro-scale, air-cathode and membrane-less microbial fuel cell for small-scale power production, which can be potentially used as an on-chip power source for lab-on-chip applications. The single fundamental material used in most of the micro- and nano-fabrication systems is silicon. Thus, we have used it as substrate and because of its semiconducting nature, it is important to improve the contact engineering to be able to extract the highest amount of current produced by such microbial fuel cells. For improved contact engineering, it is important to increase the contact area of the anode to increase the number of electrons moving from the anode to the cathode. In addition to the conventional anode material, gold, we also experimented with a low-cost alternative, nickel. After depositing them on silicon using sputtering, we annealed the nickel sample at a certain temperature and time to form nickel silicide (NiSi). This provides a balanced platform to understand the Ohmic versus Schottky contact study. Additionally, we studied the wire bonding of gold and soldering of copper wires to these materials and observed the contact resistance variation and mechanical integrity of such system, comparing the final output power generation of each system. Our study thus provides valuable insight for future study relevant to microbial fuel cell fabricated on silicon platform.

In recent years, interest in the use of cellulose fibers has intensified due to its various industrial applications, its potential use in the fabrication of green plastic composites for applications in technological devices, and low cost. Although cellulose is abundant in nature, it is not a trivial process to obtain cellulose from biomass sources due to the presence of other interfering non-cellulosic materials. Hence, in this study, crystalline cellulose was extracted from agricultural waste biomasses (i.e., wheat straw, peanut shells, and Hibiscus) and chemically functionalized using the Albright-Goldman and Jones Oxidation methodologies to increase its hydrophobicity and thermal stability of the polymer at elevated temperatures. Fourier transform infrared analysis reveals that oxidation of the cellulose polymer occurs without degradation of the polymer structure. In addition, x-ray diffraction analysis revealed that functionalization of the cellulose structure induced a polymorphic change in the crystal structure (CI to CIII). In addition, thermal measurements of the functionalized cellulose showed a dramatic increase in the thermal stability at high temperatures.
Acknowledgements: The authors gratefully acknowledge the National Science Foundation under Grant Nos. NSF EPS-1158862, NSF HRD-1137681, and NSF IGERT on Sustainable Electronics DGE-1144843 for support of this research.

In this study, removal of heavy metal ions (Pb(II) and Ni(II)) from aqueous solutions by modified mullein (Verbascum cheiranthifolium BOISS. var. cheiranthifolium) plant material was investigated. Effects of modification method on the adsorption capacity improvement for removal of these heavy metals ions have been investigated. Structures of modified mullein plant materials before and after modifications process were examined by the FTIR and SEM analyses. Modification processes were performed using HCl acid solutions. The investigations of kinetic, isotherm and thermodynamic parameters were also studied for HCl modified mullein plant material. The regeneration processes were studied for the determination of modified mullein plant material&’s reusability after the adsorption processes. Additional costs for applied modification processes were calculated and compared with the other classical methods. The chemical oxygen demand residues in treated water by modified mullein plant material comparing raw materials were decreased from 910-1430 mg/L to 10-90 mg/L with the modification processes. The removal efficiencies changed with heavy metal concentration in water sample and increased about 70% for modified mullein plant material. Heavy metal adsorption capacities were found maximum about 90 mg/g according to type of adsorbent and modification process. As a consequence, it was revealed that adsorption capacities and costs efficiency of adsorbent were compatible with conventional adsorbents.

The increasing demand for high-energy density rechargeable batteries for electric vehicles and grid storage has sparked a concerted research effort toward lithium-sulfur (Li-S) batteries. The inexpensive and environmentally benign sulfur cathode offers a high theoretical capacity of 1672 mA h g^-1, which is an order of magnitude higher than those of the conventional insertion-compound cathodes. However, the commercialization of Li-S cells is hampered by several technical challenges: (i) the insulating nature of sulfur and its discharge end products (Li₂S₂/Li₂S) and (ii) severe polysulfide diffusion (Li₂S_x, 4 < x le; 8) during cell cycling and resting. These cause low electrochemical utilization, fast capacity fading, poor discharge/charge efficiency, and severe self-discharge. To address these scientific issues, current Li-S technology has focused on improving the electrical conductivity of the “composite” cathode and localizing polysulfides within the cathode region of the cell. These promising approaches include sulfur-porous carbon composites, sulfur-conductive polymer composites, binder/electrolyte additives, and cell configuration modifications. These approaches function as various kinds of quick cures and have achieved enhanced active material utilization, suppressed polysulfide diffusion, and improved cyclability. Although these quick cures mostly overcome the original scientific challenges, they impose unfavorable side effects: (i) a low sulfur content/loading in the composite cathode, (ii) increase in cell weight on adding novel but extra cell components, and (iii) complex fabrication processes.
Here, we present a bifunctional separator with a lightweight carbon coating for use with pure sulfur cathodes. The carbon-coated (C-coated) separator integrates two necessary, cost-effective, and commonly used components that are already present inside the cell: the Super P conductive carbon and the Celgard polymeric separator. The architecture of the C-coated separator consists of a layer of conductive carbon coating onto one side of the Celgard separator. The bifunctional carbon coating functions as a conductive upper-current collector and a “containment building” for, respectively, improving the electrochemical utilization and suppressing the “polysulfide leak.” The Celgard separator serves as the electrically insulating membrane while allowing the transport of lithium ions. As a result, the C-coated separator allows pure sulfur cathode to reach a high initial discharge capacity approaching 1400 mA h g^-1 and a reversible capacity of 828 mA h g^-1 after 200 cycles. The C-coated separator also minimizes the self-discharge rate of pure sulfur cathodes to as low as 0.19 % per day after resting for three months. Moreover, the carbon coating weighs only 0.2 mg cm^-2, overcoming the drawbacks of the added weight from the conductive additives in the composite cathodes and the novel interlayer components employed in cell modifications.

Hydrogen storage is still one of the key barriers to overcome to make the switch from relying on fossil fuels to hydrogen fuel. Compared to petroleum based fuels, hydrogen has greater energy content by mass and is regarded as a clean energy carrier because its only by-product of combustion is water. Due to their low hydrogen adsorption enthalpy in the range of 4 to 10 kJ mol^-1, hydrogen storage materials that use physisorption to store hydrogen work well at 77 K but do not retain their capacity at 298 K. At the other end of the scale metal and complex hydrides tend to have high gravimetric capacities but due to higher hydrogen adsorption enthalpies (50-70 kJ mol^-1) have problems with reversibility and recycling of the materials. The Kubas interaction is where dihydrogen forms a non-classical side-on bond with a transition metal. This type of interaction falls into the 20-30 kJ mol^-1 hydrogen adsorption enthalpy range which has been predicted to be required for room temperature hydrogen storage¹.
Recent findings from the Antonelli research group have demonstrated that a series of first row transition metal hydrides can store hydrogen at ambient temperatures via the Kubas interaction². A titanium (III) hydride gel demonstrated a reversible hydrogen storage capacity of 3.49 wt% at 140 bar and 298 K without saturation. The Raman spectra of titanium (III) hydride at 100 bar H₂ showed a signal at 2903 cm^-1 corresponding to Kubas bound H₂. This was the first example of a material that uses hydride ligands as a structural feature whilst being able to bind further hydrogen via the Kubas interaction³. We have extended this work and have also prepared an amorphous chromium (II) hydride gel that stores 5.07 wt% hydrogen at 150 bar and 298 K which is close to the US Department of Energy&’s gravimetric capacity target for 2017. The adsorption isotherm is linear and does not saturate at 150 bar indicating that higher performance could be seen at higher pressures. The material stores hydrogen reversibly and did not lose activity over 10 repeated adsorption-desorption cycles. We recently also reported an iron(II) hydride gel whilst not being a good candidate for hydrogen storage could potentially be used in catalysis⁴. This talk will discuss the synthetic approach for these materials, as well as physical characterization and hydrogen storage properties of these new solid state transition metal hydride gels.
References
(1) Zhao, Y.; Kim, Y.-H.; Dillon, A. C.; Heben, M. J.; Zhang, S. B. Phys. Rev. Lett.2005, 94.
(2) Antonelli, D. Novel Metal Hydrides and Their Use in Hydrogen Storage Applications. WO2013088170 (A1), June 20, 2013.
(3) Hoang, T. K. A.; Morris, L.; Reed, D.; Book, D.; Trudeau, M. L.; Antonelli, D. M. Chem. Mater.2013.
(4) Morris, L.; Trudeau, M. L.; Lees, M. R.; Hanna, J. V.; Antonelli, D. M. J. Alloys Compd.2014, 590, 199.

This work studies the mineralogical and chemical characterization of ceramics with addition of iron ore processing tailings. To optimize the procedure of preparing additives from iron ore tailings for the production of new ceramics and to determine their effects on the final properties of the materials produced, they were added in ratios of 0 % to 50 % in substitution to traditional aggregates [1]. Thus, to study the physical, chemical, optical and morphological properties of mineralogical phases present in the ceramics, they were characterized by an Integrated Mineral Analyzer, associated to a field emission SEM. As the built-in mineral analyzer database is composed of a finite set of mineral spectra, based on data collected from samples originated in deposits outside the Brazilian territory, a substantial part of the analysis was performed constructing a new database for the particular materials used in the ceramics. This allowed the establishment of a fully automated method for the mineral characterization of gangue phases for Brazilian iron ores. For the calibration of the results, the data obtained was cross checked with optical microscopy, x-ray diffraction, x-ray fluorescence and electron microprobe analysis.
Acknowledgments: This work was supported by CNPq, Fapemig, Fundaccedil;atilde;o Gorceix and UFOP.
References
[1] SILVA, F. L. et al, Recycling of Concentration Tailings of Iron Ore for the Production of Concrete Block (Pavers), Materials Science Forum - 2014.

The ceramic industry is the one that stands out in the use of industrial tailings, replacing pure raw materials by part these materials. Both technologically and economically, this segment is a good option for the recycling of solid waste. This work aims to study the feasibility and sustainability, from the economic and technological points, for the of use iron ore tailings as additives in the ceramic industry. To study the chemical, physical, morphological and optical properties of the tailings and clay, chemical, mineralogical and granulometric analysis were carried out. Specimens were formulated with different ceramic compositions at levels of 0 and 5 % of tailings added in commercial clay and sintered at a temperature of 950°C. The ceramics were characterized for color and mechanical properties. Results indicated that the addition of tailings from concentration of iron ore for the production of red ceramics was highly feasible both technically and environmentally.

The effect of anion type in ionic liquid on transition of crystalline structure was studied using lignocellulosic biomass pretreated with 1-ethyl-3-methylimidazolium acetate (EmimOAC) or 1-ethyl-3-methylimidazolium chloride (EmimCl). The influence of the pretreatment on the composition and crystalline structure was observed by Fourier-transform infrared (FTIR), compositional analysis, thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD). Dependency on lignin content and transformation from cellulose I to II was related with anion type in ionic liquid. Comparing to EmimCl, EmimOAC pretreatment substantially decreased the cellulose as well as the lignin, coinciding with decrease of cellulose molecular weight. The biomass samples recrystallized only in EmimOAC whereas coexistence of cellulose I and cellulose II was observed from samples pretreated with EmimCl.

The Rare Earth Elements (REEs) are becoming increasingly important for global economy due to their increasing usage in a variety of applications ranging from permanent magnets, wind turbines to hybrid and electric cars. Some of these REEs are becoming increasingly critical due to a global imbalance between the existing supply and demand chain. While sustainable primary mining from old and new REE deposits is being exploited as the first response to mitigate the REE supply risk, comprehensive efforts are also being made towards recycling of REEs from End-of-Life Material Streams. We aim to complement these recycling efforts by developing processes and technologies to recycle REEs from industrial waste water residues. We intend to exploit the phage display technique to identify peptide sequences that can selectively bind the target REE. The peptide sequences displaying strong binding affinity towards target REEs will be first screened using microscopic and spectroscopic methods and further characterized with SPR (Surface Plasmon Resonance) and QCM (Quartz Crystal Microbalance) to obtain quantitative binding kinetics. Eventually, we hope to convert these peptides into smart and hybrid biomaterials for biomining applications under industrial conditions. Details of the current work and progress focused on three REEs (namely Yttrium oxide, Dysprosium oxide, and Europium oxide) will be discussed.

Dust deposition on the top of solar collectors is a significant source of efficiency loss ranging from 10% to 50% depending upon location. Unfortunately the dry, arid regions that are ideal for solar energy due to their high direct irradiance are also prone to high soiling rates. The prevailing dust mitigation techniques involve water deluge and mechanical scrubbing that are both water intensive and costly. Electrodynamic screens (EDS) can be used as an alternative approach to clean the dust particles without the water and high labor cost. An EDS system consists of parallel electrodes embedded within a transparent dielectric film and deposited on the front of PV modules and solar mirrors. When activated the dust particles on the surface of the film become electrostatically charged and are removed by a three-phase alternating electric field.
In order for the EDS to be a viable cleaning alternative it must be integrated into a solar collector with minimal impact on the device&’s power output. Because the EDS sits above solar collector surface the electrode material used must be highly transparent or, in the case of concentrating mirrors, have a high specular reflectivity. In addition to the optical properties, for effective EDS operation the electrodes need to have a high conductivity and excellent outdoor durability. Furthermore, to make the system cost effective the electrode material should have a relatively low material cost and compatible with a large-scale manufacturing process such as gravure or screen- printing. Several transparent conductive materials have been investigated for this purpose including: PEDOT: PSS, ITO, aluminum doped zinc oxide, and silver nanowire. EDS were constructed from candidate materials and tested for their dust removal efficiency and initial optical transmission. In order to gauge overall effectiveness of these materials in an EDS system a figure of merit was developed. These results are discussed as well as cost and processing considerations for each material.

High performance biodegradable polymer nanocomposites are able to play very important roles of maintaining energy sustainability and preventing white pollution caused by polymer products overutilized. Montmorillonite clays and Halloysite nanotubes (HNTs) were modified by surface adsorption of resorcinol di (phenyl phosphate) (RDP) oligomers. Biodegradable poly (lactic acid) (PLA) and poly (butyleneadipate-co-butyleneterephthalate) (PBAT) polymers were blended together with either, RDP coated montmorilonite clays, RDP coated HNTs, Ditallow functionalized clays (Cloisite 20A), unfunctionalized sodium clays and HNTs. The thermo-mechanical response of the samples were directly compared in order to determine the role of the particle morphology (tube vs sheet) on the materials properties. TEM images of thin sections indicated that even though both clay nanotubes and platelets, regardless of coating, segregated to the interfacial region between the two immiscible polymers, only the platelets, having the larger aspect ratio, were able to reduce the domain sizes. The ability of clay platelets to partially compatibilize the blend was further confirmed by the dynamic mechanical analysis (DMA) which showed that the glass transition temperatures of two polymers tend to shift closer. No shift was observed with either coated or uncoated HNTs samples. Izod impact testing demonstrated that the rubbery PBAT phase greatly increased the impact strength of the unfilled blend, but addition of only 5% of clay filler decrease the impact strength by nearly 50% while a small increase was observed with nanotubes at that concentration. The differences in tensile toughness were even more dramatic, where the toughness decreased by nearly 500% with clays, while that for the nanotubes samples was negligible. A simple model is proposed. The clay platelets are observed to cover the interfacial area. Although they are effective at reducing the interfacial tension, they increase the overall brittleness, and facilitate micro-crack initiation and propagation. On the other hand, the HNTs are observed to lie perpendicular to the interface, which makes them less effective in reducing interfacial tension, but far more effective at blocking micro-crack propagation.

Investigation of optical properties of fuel oils and its mixtures with ethanol has significant interest among both public and scientific communities. Public community would like to be ensured of purchased product quality, and scientific community would like to have a better understanding of the complex mixtures; especially the role of intermolecular forces on relaxation dynamics of solvent and solute molecules. In this study, the optical properties of fuel oils and their mixture with ethanol have been investigated by Fourier transform and Time-Domain Terahertz (THz) Spectroscopy covering a wide spectral range of 5 cm^-1 to 400 cm^-1. Frequency dependent absorption coefficients, refractive indices, and dielectric constants were calculated from the measurements of pure fuel oils and their mixtures with ethanol. Ethanol mixtures of gasoline were modeled successfully with a simple model in which the mixture behavior was described with a basic contribution approach of pure liquids. The results suggest that there is no strong interaction between ethanol and molecules in the gasoline. As the mixing ratio changes meaningful shifts are observed in the frequency dependent refractive index and absorption coefficients associated with the dominant component, ethanol. We concluded that this new approach offers a simple and useful method to determine the concentration of ethanol in gasoline with ca. 1 % error (by volume) with respect to the actual ethanol percentage. There are specific bands associated with the certain components of the gasoline by which the fuels can be separated according to their octane ratings. Fuels have also been investigated according to the suppliers and clear differences have been observed. The measurements and analysis presented here show that both Fourier transform and time-domain terahertz studies can offer invaluable insight for modeling complex mixtures and can be safely used in characterization of fuels according to their types and/or octane ratings.

Increasing energy demands have inspired intense research efforts toward alternative energy conversion and storage systems with high efficiency, low cost and environmental benignity. Since oxygen evolution reaction (OER) plays key roles in many electrochemical processes such as solar fuel production (water splitting), development of more efficient and durable catalysts is crucial to future advances in these fields. Although precious metal oxide catalysts like RuO₂ and IrO₂ exhibit high activity, their large-scale applications are impeded by prohibitive cost and scarcity. Certainly, developing effective catalysts from earth-abundant elements to substitute high cost catalysts is highly demanding.
In the present work, we have discovered a novel OER-active cobalt-based material which can be in-situ generated from nanoparticular cobalt phosphides (CoP). Catalyst activation phenomenon was detected in OER polarization curves obtained at initial successive scans. We also observed dramatic morphology changes of CoP when it was exposed to high potential region where OER occurred. Original rod-shaped CoP nanoparticles (~20 nm) are changed to become porous nanoweb-like architectures. At the same time, its electronic structures were significantly varied along with the morphology changes. Our post-catalytic XPS and XAFS studies clearly indicated that Co-Pi like nature was obtained in-situ while CoP nanoparticles experienced high potential. Generation of phosphate species (PO₄^2-) as well as enhancement of cobalt (ge;III) species bound to oxygen was confirmed by the XPS and XANES spectra. Our EXAFS analysis also displayed distinctive structure transition of original CoP during OER.
Remarkably, the in-situ generated active Co-Pi like catalyst showed excellent OER efficiency and durability in alkaline electrolyte (0.1M KOH) even with a low catalyst loading (~0.08 mg_Co/cm²). A current density of 10 mA/cm² (which is a frequently used standard metric in OER literatures) was achievable at a small overpotential of ~0.36 V with the present catalyst which is favorably comparable or superior to the best reported OER active materials such as Mn₃O₄/CoSe₂ nanocomposite and Co₃O₄/N-graphene and even the precious iridium catalyst. Furthermore, the catalyst afforded minute performance deterioration even after 1000 cycles of high potential ranges (1.3-1.7 V, 100 mV/s) while Ir/C and Co3O4/C recorded more than 30 mV increment of overpotential at 10 mA/cm² under the same condition.

We present vanadium dioxide nanoparticle smart window prototypes with the capacity to passively modulate the transmission of solar energy into a building. This is an emerging high-performance class of thermochromic window in which sub-100nm vanadium dioxide particles are encased within a polymer film. The energy saving ability of these coatings is large and the potentials for retrofitting and low-cost production are extensive.
Our continuous-hydrothermal route to synthesising vanadium dioxide nanoparticles will be presented. Additionally, our approach towards dispersing these particles and embedding them within the polymer host with a variety of concentrations will also be discussed.
A series of Finite Difference Time Domain simulations of thermochromic nanoparticles in a plastic host yields design rules for this system predicting optical behaviour such as scattering around the particles. These predictions are compared against measurements of our fabricated prototypes.

Nanotechnology is considered to be one of the key technologies of the twenty-first century with high expectations for innovative products and new market potentials, the exposure to nanoparticles may also lead to environmental risks and adverse health effects. The global production and use of nanoparticles increased and are estimated to be over half a million tons by 2020 [1]. According to this it is almost certain that engineered nanoparticles will be released into the environment [2]. To avoid these risks in this work is presented the systematic evaluation of the complete destruction a polymeric nanoparticle by the use of custom-built system of high-temperature and high-pressure (HTHP) water. This emerging technique can provide complete decomposition of nanostructured wastes such as PLGA nanoparticles.
In our studies we have evaluated the efficiency of degradation of nanotechnologic waste material using the technique of UV-visible, fluorescence emission, FTIR and dynamic light scattering (DLS), that are a non-invasive, well-established technique for measuring the size and size distribution of particles typically in the submicron region.
The results obtained were satisfactory although we believe that the reactor configurations can be improved for the study of the degradation of biopolymers in supercritical water
This work was supported by CNPq, CAPES, FINATEC, DPP-UnB and FAPDF.
Reference:
[1] M. A. Maurer-Jones. Analytical Chemistry. 85, 3036minus;3049, (2013).
[2] B. Nowack. Environmental Pollution. 150, 5-22, (2007).

Natural gas is considered the cleanest and recently the most abundant fossil fuel source, yet when it is extracted from wells, it can contain significant amounts of CO₂ which is generally vented to the atmosphere. Efforts are underway to contain this CO₂ at the well-head using inexpensive and non-corrosive methods. Here, nucleophilic porous carbons are synthesized from simple and inexpensive carbon-sulfur and carbon-nitrogen precursors. Infrared, Raman and ¹³C nuclear magnetic resonance signatures substantiate CO₂ fixation by polymerization in the carbon channels to form poly(CO₂) under much lower pressures than previously required. This growing chemisorbed sulfur- or nitrogen-atom-initiated poly(CO₂) chain further displaces physisorbed hydrocarbon, providing a continuous CO₂ selectivity. Once returned to ambient conditions, the poly(CO₂) spontaneously depolymerizes, leading to a sorbent that can be easily regenerated without the thermal energy input that is required for traditional sorbents. This process can be further extended to the use of asphalt as the starting material for the nucleophilic porous carbons. In addition, the same materials can be used for trapping H₂S.

The effect of increasing atmospheric CO₂ concentration on global climate change is recognized as one of the most important environmental issues facing society today. The levels of CO₂ in the atmosphere have reached daily averages of 400 ppmv at Mauna Loa observatory as of May 2013, an increase of over 100 ppmv from the pre-industrial era. Although amine-based absorption is the current state-of-the-art technology for capturing CO₂, it is not clear that absorption technologies alone will lead to the cost reductions required to achieve a gigaton-scale solution to CO₂ emissions, due to the high energy consumption for solvent regenration. Adsorption-based technologies for CO₂ capture have several advantages over the traditional amine-based solvent absorption approaches, including relatively low regeneration energy, tunability on pore strctures and flexibility on suface chemical modification. In addition, materials such as carbon possess favorable heat conduction properties.
Mesoporous carbons are promising for CO₂ capture due to their chemical inertness, low cost, high surface area, and tunable pore structures. Nitrogen functionalization plays an important role in surface chemistry to achieve enhanced CO₂ adsorption capacity. We report here an hierarchical mesoporous nitrogen-doped carbon made using the co-assembly of modified-pyrrole and triblock copolymer through a soft-templating method, which is facile, economical, and fast compared to the hard-template approach. In the synthesis process, the pyrrole precursor acts as both the carbon and nitrogen source. Carbonization of the resultant polymeric assembly generates a graphitic carbon structure and porous network through the removal of the block copolymer template. The resulting material shows promising CO₂ capture performance, reaching equilibrium adsorption of 1.0 mmol and 3.2 mmol CO₂/g of material (25 °C, 0.1 bar and 1 bar, respectively). The mesoporous carbon was further subject to a KOH activation process to create more micropore and surface area. The pore size distribution and CO₂ capacity were found to be easily tunable by varying the carbonization and activation temperatures. The maximum CO₂ loading capacities were found to be 1.3 mmol and 5.1 mmol CO₂/g of material (25 °C, 0.1 bar and 1 bar, respectively) on different samples. The CO₂ adsorption and desorption are completely reversible for multiple cycles under mild desorption conditions. Furthermore, the hierarchical macro-meso-microporous structure of this N-doped carbon allows for fast diffusion of CO₂ gas into the adsorption sites and controlled pore condensation within the microporous structure. These properties of mesoporous carbons made from a conducting polymer render these as desirable materials for CO₂ capture.

: Carbon dioxide (CO₂) is a very important contributor to the greenhouse effect. To reduce its presence in the atmosphere many materials are being study to adsorb CO₂. To be considered a suitable material for CO₂ adsorption there are four main properties that the material should feature (i) good adsorption capacity towards CO₂, (ii) high selectivity, (iii) full regeneration capacity with a minimum energy input, which allows the reutilization of the material for CO₂ adsorption, and (iv) cost and environmental friendliness of the capturing material. Using x-ray diffraction we show that gaseous CO₂ intercalates into the interlayer space of smectite clay (fluorohectorite) at conditions close to ambient. The rate of intercalation is found to be dependent on the interlayer cations, which in the present case are Li⁺, Na⁺ and Ni²⁺. We further show that Li-fluorohectorite is able to retain CO₂ in the interlayer space at room temperature, which could have applications related to CO₂ capture, transport and storage. De-intercalation starts occurring at temperatures exceeding 30 °C for Li-fluorohectorite and -5 °C for Na-fluorohectorite, while Ni-fluorohectorite shows a strong interaction towards the CO₂ molecules and does not exhibits the same de-adsoption behavior as observed in the other samples.

Heterogeneous interfaces often exhibit remarkable material properties resulting from their unique interface structural motifs, and it is extremely challenging to manipulate and design interface structures at the atomic level to achieve new functionalities. We demonstrate that the CO₂ capture activity of rutile TiO₂(110) coated by one monolayer of alkanolamine can be controlled by modifying the length of the backbone in alkanolamines, measured by synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS) at near-ambient CO₂ pressures. Adsorbed 2-amino-1-ethanol (monoethanolamine, MEA) is inactive, whereas amine group in 3-amino-1-propanol (3AP)/TiO₂(110) readily reacts with and captures CO₂. Density functional theory (DFT) study revealed that the CO₂ capture activity is dictated by the interfacial molecular packing density, and the interaction between the amine group and the five-fold coordinated Ti atom (Ti_5f) on the surface. In MEA, the distance between O and N atoms matches well with the Ti - Ti spacing along the surface (001) direction. This leads to a densely packed monolayer of MEA, which blocks the access of CO₂ to the amine group as the binding site. Furthermore, the amine group binds strongly to the substrate with a N-Ti_5f bond length of 2.23 Å, essentially deactivating CO₂ capture. In contrast, the additional C atom in the backbone of 3AP creates a length mismatch with the Ti - Ti spacing, making the 3AP monolayer loosely packed. Compared with MEA/TiO₂, the N - Ti_5f bond in 3AP/TiO₂ is significantly weakened with an elongated bond length of 2.36 Å. Consequently, exposure of the 3AP/TiO₂(110) to 0.2 Torr of CO₂ gives rise to a C(1s) peak at the binding energy of 289.6 eV, which is attributed to captured CO₂. Our results suggest that such geometric effects may be exploited in CO₂ capture by solid-supported alkanolamines and other functionalized molecular species, which is a promising alternative to aqueous alkanolamine solutions for the large-scale capture of CO₂.
Research carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.

Human energy production heavily relies on fossil-fuels that release enormous amount of CO₂. Efficient carbon dioxide capture and sequestration (CCS) is of enormous research interest for sustainable energy supply. Post combustion gas from power plant, namely flue gas, accounts over 40% of entire CO₂ emission so effective treatment of flue gas is the key area of CCS. Currently, industrial flue gas control is principally based on the wet chemical absorption employing aqueous amine solvents, such as monoethanolamine and diglycolamine. Unfortunately, energy cost for the regeneration of liquid absorbents is generally high, and the corrosive and oxidative degradation of process equipment under acidic operating conditions raises significant effort for maintenance. A promising alternative method for CCS is to use porous solid adsorbents. Solid adsorbents may offer facile desorption and regeneration through temperature or pressure control, which is highly desirable for efficient recyclable process. Carbon adsorbent is attractive adsorbent for CO₂ capture with multiple advantages including cheap and abundant material supply, high thermal stability, and large adsorption capacity at high pressure due to the presence of meso- and macropores. Nonetheless, their non-specific weak van der Waals force based interaction with CO₂ limits adsorption capacity and selectivity.
Here we report a unique example of carbon nitride functionalized porous carbon adsorbent with highly selective, easily regenerative, and efficient CO₂ capture functionality. Three dimensional porous frameworks of graphene oxide decorated with amorphous carbon nitride motif is constructed through modified graphene oxide gelation principle. Resulting materials exploits both porous graphene backbones which readily introduce incoming gas molecule and stably supports carbon nitride groups, and defect-rich carbon nitride sites with. Amorphous carbon nitride sites on graphene surface include multiple amine groups capable of reversible CO₂ capture functionality through favorable binding energy and mutually oriented adsorption sites. We deliberately designed this material to possess intermediate level of CO₂ adsorption strength between physisorption (0.1 eV) and chemisorption (0.5 eV) which offer moderate adsorption capacity (0.43 mmolmiddot;g^-1 at 0.1 bar, 300K), excellent regenerability (R = 97.6%), high selectivity (α₁₂^ads = 87) and large sorbent selection parameter (S > 500) value. This result suggests unique approach in designing biocompatible, economical, stable and sustainable flue gas treatment with carbon adsorbent.

Nanoporous materials have high capacity of adsorption amount thanks to their narrow pore size. In addition, the number of adsorbed molecule is one or two locating between absorbent pore wall atoms. It is very interesting to characterize interaction between adsorption molecule and adsorbent pore wall. We characterized the flexible porous coordination polymers (PCPs/MOFs) and Silicalite (MFI zeolite) with the adsorption/X-ray powder diffraction (XRPD) coincident measurement system.
The high silica MFI zeolite is interesting because of its selectivity by pore size and its hydrophobicity surface for separation and adsorption applications. Its crystal structure phase transition was well defined with single crystal X-ray diffraction. Density change of adsorbate in the pore was also discovered through adsorption research. In this process, the Syncrotron-radiation powder diffraction (SPRD) experiments were carried out by the in situ adsorption condition installed in the BL44B2 beam line of SPring-8 at RIKEN. We observed N₂(@77K) and Ar(@87K) on MFI zeolite (Si/Al=500) powder showed phase transition of MFI structure from monoclinic to orthorhombic, and simultaneously adsorbate molecules formed orderly packing structure at a certain location in the nano-sized pore. The adsorbed amount in the pores is evaluated to be 32 molecules/unit-cell from SRPD data and the figure matches the adsorption isotherms. During adsorption and phase transition of MFI zeolite, we found the main straight channel pore changed it shape flexibly from round to oval by the adsorption of Ar and N₂. Furthermore, the average center-center distances of Ar or N₂ in the pores are shorter than those of the bulk solid distances.
The flexible PCPs are new functional nanoporous adsorbents. Some flexible PCPs show highly guest-selective adsorption or unusual abrupt guest inclusion at higher relative pressure region called gate opening type adsorption. Because the adsorption properties of flexible PCPs are often related to changes of the pore structure, it is important to obtain information about structural change as well as adsorbed amount to elucidate sorption mechanism. We prepared a new flexible PCP composed of 5-azidoisophthalate (aip) and divalent Cu²⁺ ions. The PCP showed reversible structural transformation upon carbon monoxide sorption. In this process, the coincident measurement system of adsorption and XRPD were formed through connecting powder X-ray diffractometer (SmartLab/RIGAKU) and volumetric adsorption apparatus (BELSORP-18/BEL JAPAN). We found this PCP showed a stepwise adsorption profile. The XRPD patterns were abruptly changed at the 2nd step in the adsorption. According to the structural analysis, the coordination of CO to Cu²⁺ site induces a global structural change that creates a suitable compartment for further accommodation of CO molecules. Thank s to the uqique sorption property of the flexible framework, CO separation from gas mixtures with N₂ was also realized.

Activated carbon fiber (ACF) was fabricated by annealing and activating cotton with ZnCl₂ (concentrations 72 to 115 g/liter) in argon at temperatures ranging from 400^oC to 700^oC. The ACF product retained the original fibrous structure of cotton. The diameter of the fiber was 15 mu;m, slightly thinner than that of cotton. In their Raman Scattering spectra, two major peaks were found at 1350cm^#8210;1 and 1590cm^#8210;1 which corresponded to the D and G bands of amorphous and graphitic carbon, respectively. The Fourier Transform Infrared Spectroscopy revealed that the fiber surface possessed large number of carboxyl groups which would enhance anchoring of adsorbates during adsorption. The surface area and porosity of the sample were evaluated by nitrogen gas sorption surface analysis. The Langmuir specific surface area, BET surface area, and pore volume were found to be 2793 m²/g, 2060 m²/g, and 1.002 cm³/g, respectively. The majority of pore size fell into the range between 1.9 nm and 3 nm. The adsorption ability of the ACF product was evaluated in the presence of methylene blue (MB) in water of different pH levels. The adsorption behavior of sample was well interpreted by the pseudo-second order kinetics model. Results also indicated that the ACF sample was more effective in adsorbing MB in alkaline condition. The monolayer adsorption capacity for the MB was determined to be about 597 mg/g, and was one of the largest among similar activated carbon products, owing to its large BET surface area. Activated carbon is one of the most suitable adsorbents for vapor recovery due to its micro-porous nature. In this work, the potential application of our ACF product as a low cost eco-adsorbent for the recovery of organic solvent vapors (including methanol, ethanol, acetone, moisture) was also investigated. The post activated treatments on the ACF samples such as oxidation by nitric acid or hydrogen peroxide was performed before their pore structure and chemical properties were examined. The porous structure had provided large adsorption capacity in the ACF sample. The total mass of the sample as function of time was determined during adsorption of various organic vapors in saturated vapor condition at ambient. Results showed that mass of sample increased with time, but the adsorption rate decreased with time. The rate of mass gain in the sample was found different for different type of vapor: acetone > methanol > ethanol > moisture. The adsorption of moisture did not reach equilibrium even after 2 h while it only took 2 min for acetone vapor to reach equilibrium. The rate of adsorption was mainly depended on the saturated vapor pressure of the solvents. In desorption of adsorbed species from the ACF sample, only 200^oC was required for the complete removal. Our results also demonstrated that low activation temperature (500^oC) and higher concentration ZnCl₂ (>115 g/liter) were the keys to produce ACF samples having large pore volume and high vapor adsorption ability.

Separations of gaseous mixtures are critical to energy, petrochemical, food, and heath industries. Commercially practiced large-scale gas separations (e.g. air separation, acid gas removal from natural gas, and olefin/paraffin separations) are usually realized by distillation or absorption. These conventional separations are expensive and require significant consumption of thermal energies per unit of product.
Membrane separation is an energy-efficient and sustainable alternative to traditional thermally-driven separations. “Carbon footprints” of membrane processes can be as much as an order of magnitude lower than traditional thermally-driven separations. CMS membranes and mixed-matrix membranes (MMM) offer substantially enhanced separation performance over pure polymer membranes while offering relatively low manufacturing costs. Conventional CMS membranes are formed by pyrolyzing pure polymer precursors. On the other hand, traditional mixed-matrix membranes are prepared by dispersing molecular sieve particles (e.g. zeolites and MOFs) in polymer matrices. Both CMS membranes and MMM have been extensively studied; however, a combination of MMM and CMS realized by dispersing molecular sieve particles in CMS matrices has been rarely reported.
This talk will focus on formation and characterization of novel membranes for sustainable gas separations formed by pyrolyzing MOF/polymer precursor mixed-matrix materials. By controlling pyrolysis temperatures and protocols, the polymeric matrix can be transformed into amorphous CMS while the crystallinity of dispersed MOF particles is retained. Gas permeation measurements show that the resulting MOF/CMS mixed-matrix membrane had superior gas separation performance over the MOF/polymer precursor mixed-matrix membrane.

Indoor air quality has a significant impact on human health. Currently indoor odor management relies on energy-intensive heating, ventilation and air conditioning (HVAC) systems, on single use volatile organic compounds (VOC) adsorbers or ozonation technologies. Energy consumption for HIVAC can reach up to 50 % of the total building consumption [1]. In this area a huge potential for energy saving and environmental friendly technologies is given. Ceria based catalyst are widely used materials for exhaust air treatment [2-4]. This study investigates a more sustainable, multi-cycle use of an odor adsorber system that combines concepts from catalytic oxidation and air cleaning [5]. Both pure and sodium doped, nanostructured CeO₂ were tested as adsorber material for high volume removal of odorous compounds from air. As a representative compound for unpleasant odors, hexanoic acid (HA) was used. After air cleaning on fixed beds of CeO₂ or Na/CeO₂, both hexanoic acid loaded adsorber materials were heated under air and displayed considerable oxidation activity at 190 °C and 260 °C, respectively. Mass spectroscopy was used to confirm that no hexanoic acid desorbed during combustion. CeO₂ was regenerated at 220 °C in air and could be successfully re-used as adsorber without noticeable loss in performance. The study demonstrates that CeO₂ has most promising properties for application as re-usable air cleaner due to its very good ability for adsorption even at highly dilute conditions (ppm-level) using a representative acidic test compound with rancid and sweaty odor. Sodium as a basic dopant further improved the adsorption of hexanoic acid but requires a higher regeneration temperature.
1) L. Perez-Lombard, J. Ortiz, Ch. Pout, Energy and Buildings, 2007, 40, 394-398
2) A. Trovarelli, C. de Leitenburg, M. Boaro, G. Dolcetti, Catal. Today, 1999, 50, 353-367.
3) A. Trovarelli, Catal. Rev. 1996, 38, 439-520.
4) M. Mogensen, N.M. Sammes, G.A. Tompsett, Solid State Ionics, 2000, 129, 63-94.
5) R. A. Raso, A. Stepuk, D. Mohn, D. Paunescu, F. M. Koehler and W. J. Stark, Appl. Catal. B, 2014, 147, 965-972

Zeolites are an important class of materials characterized by a microporous crystalline structure. Most of their applications rely on the fact that pores have dimensions which are comparable with the size of the molecule which can be adsorbed. Hence, their sorption isotherm can be tailored to a specific adsorbent by adjusting pore size, framework structure and composition. They are widely used as selective adsorbents for the removal of carbon dioxide, water vapor and other impurities form hydrocarbon mixtures, or as catalysts which adsorb and convert hydrocarbon molecules. There are also promising materials for thermochemical energy storage applications, whereby heating and cooling technologies use thermo-adsorptive effects. Adsorption by these microporous materials in the presence of water vapor is studied in order to provide information on adsorption capacities and energy requirements for regeneration of adsorbents. In order to gain deeper understanding of their adsorption capacities after several water adsorption/desorption cycles, isotherm measurements over a wide range of vapor pressures and temperatures have to be performed.
This paper highlights a new experimental method for determining gas or vapour adsorption isotherms on zeolite materials. Using a novel dynamic flow configuration, this gravimetric experimental system can measure both competitive multicomponent adsorption processes as well as adsorption a very low partial pressures where static adsorption is inaccurate. This method can not only be used across a wide range of temperatures, but is well suited for adsorption studies using gases as well as vapours at high partial pressures.
Adsorption data obtained using condensable vapours from room to high temperatures, vapour adsorption data for very low partial pressures as well as data for competitive two component adsorption will be presented for a number of porous zeolite materials highlighting this unique experimental approach.

Quality of life, standard of living and national security depend on energy availability. The limited supply of fossil energy, its accelerated consumption, impact on the global climate and interface with other environmental and human challenges, and the geopolitical ramifications of its supply are major global social, economic and security issues. The development of clean, affordable energy is one of society&’s greatest grand challenges. There is a direct correlation between energy use, productivity and the standard of living. If the world population is to stabilize, the standard of living in developing nations must rise, which, in turn, implies that energy use must also rise. The cost of energy is a significant fraction of the total cost of the GDP an increase in the cost of energy correspondingly leads to a reduction in other GDP factors and, therefore, a loss in standard of living. This effect is particularly harmful in developing nations that already have an undesirably low GDP.
Energy production and use directly impact, not only the economy, but also the environment and the availability of clean water, as well as the food supply. With respect to the energy-water nexus, the near future offers unattractive possible outcomes for basic sustenance of human populations. Thermoelectric power generation alone consumes approximately 40% of the freshwater withdrawal in the United States. Similarly, the US water infrastructure consumes 13-18% of total municipal electricity usage; that portion is projected to increase with increasing water scarcity, population growth, and pollution of water resources. In addition, cleaner energy alternatives (e.g., biofuels) will significantly increase water demands that may adversely affect food supplies. Future water supplies will rely increasingly on nontraditional sources and water reuse the treatment of which will demand significantly more energy and increased attention to public assurance of safety. As currently managed, domestic wastes and wastewaters require high energy expenditures for treatment and disposal. Moreover, increased stresses on fresh water tend to lead to greater water pollution, creating an unsustainable feedback loop. Therefore, the increasing global demand for energy & water pose formidable challenges to these interconnected infrastructure systems.
Finally, global utilization of energy is responsible for the majority of anthropogenic GHG emissions and, thereby, the changing climate, adversely affecting global environment. Moreover, climate change drives enhanced weather extremes, resulting in less water availability in arid regions that can least afford it. It has been predicted that this energy-water-climate negative trifecta will have a severe impact on water and food availability for most of Africa and central Asia--almost half the world&’s population--by 2025.
These policy considerations and the role of materials technology in addressing the energy-water nexus will be discussed.

Water is one of the most important components for our life. Preservation of fresh water is one of the most important issues in sustainable development, which is called water treatment. In water treatment there are two main separated steps, separation and degradation. Many kinds of porous materials including zeolites and porous carbons were used for pollutant separation by adsorption. TiO₂ was widely used for photocatalytic degradation of pollutant. Here we report new type of inorganic-organic hybrid porous material, metal-organic framework (MOF), which can adsorb pollutant from water followed by degradation of the pollutant by light irradiation. The MOF comprising porphyrin based ligand has good stability in water unlike most of MOFs. The MOF selectively adsorb a pollutant having smaller size than its pore size, which demonstrates size selective pollutant adsorption property of the MOF. In addition, porphyrin ligands decompose the adsorbed pollutant by visible light irradiation. Therefore, the porphyrin based new MOF can serve as a new material for pollutant removal in water. Details of our recent work will be presented.

Nanodiamond Powder as Reusable Nontoxic Water Disinfection Material
Abelardo Coloacute;n¹, Jennifer Gil², Bárbara Avalos³,
Rafael Rios¹, Javier Avalos^4,5, Brad R. Weiner^5,6, Gerardo Morell^2,6
1 Department of Environmental Science, University of Puerto Rico, San Juan, PR 00936, USA
² Department of Physics, University of Puerto Rico, San Juan, PR 00936, USA
³ Department of Biology, University of Puerto Rico, San Juan, PR 00936, USA
⁴ Department of Physics, University of Puerto Rico, Bayamoacute;n, PR 00959, USA
⁵ Department of Chemistry, University of Puerto Rico, San Juan, PR 00936, USA
⁶ Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931, USA
Detonation Nanodiamond or ultra-disperse Nanodiamond (UDD) is an interesting carbon allotrope since it has a small particle size (4-5 nm), facile surface functionalization and great bio compatibility properties that can be used for many biomedical applications, such as drug delivery, surface coating and anti-bacterial/anti-viral treatments. We have carried out studies of UDD as a bactericidal agent on water treatment plants. Current US water treatment plants use chlorine to disinfect surface water, but improper management of this hazardous gas can cause lethal effects on water plant workers and water users. Moreover, disinfectant by products (DBP&’s) produced by chlorine disinfection process have raised health concerns because they can cause cancer to the population that drinks water or inhale vapor. We mixed UDD powder with river water from urban, rural and urban/rural watersheds to determine the effectiveness of UDD as a nontoxic reusable water treatment agent. Qualitative (UV and normal imaging) and quantitative data (statistical analysis) were done and the results showed strong bactericidal properties of UDD on fecal E. coli bacteria present in river water from 3 different watersheds. These promising results demonstrate that UDD can be used to disinfect fecal bacteria found in surface water bringing a nontoxic new disinfection material for water treatment plants.

Semipermeable membranes have become important materials from the viewpoint of energy and environment. Up to present, aromatic polyamides have been used as a membrane material of the active layer due to their high water flux and excellent NaCl rejection. However, PA membrane suffered from critical low chlorine resistance of amide linkage, which leads to irreversible performance loss over time and requires the expensive dechlorination and rechlorination treatment steps. Thus, the novel synthetic polymers designed to be high chlorine resistance and transport properties should be used as semipermeable membranes to address this problem. Polybenzimidazole (PBI) without amide linkage was expected to be one of the alternative materials as the active layer due to its high mechanical properties, thermal stability, and chemical stability over a wide range of pH. In spite of its excellent properties, the hydrogen bonding between N-H unit and nitrogen with lone pair in the imidazole ring is so strong that the PBI membrane has become dense and shows low water transport properties. To address this problem, it is necessary to suppress the polymer/polymer interaction and increase the free volume of PBI membrane. In this study, the N-H group in the imidazole ring was substituted to sodium-butylsulfonate group in order to suppress the hydrogen bonding and to increase the hydrophilicity. Moreover, polymer chains were crosslinked by divinyl sulfone during the dissolution process to fix the state of the polymer in solvent. PBI membranes with less than 2 mu;m thickness were prepared by spin coating the polymer solution onto the glass substrate and drying the as-cast membrane with heating. As a result, the crosslinked N-butylsulfonated PBI (BS-PBI) membrane significantly improved not only salt rejection but also water permeability (NaCl rejection : 44 %, water flux : 0.54 m³/m²/day) compared to those of non-crosslinked BS-PBI one (NaCl rejection : 11 %, water flux :0.063 m³/m²/day,). In FTIR spectra, the peak corresponding N-H stretching was shifted to higher wavenumber by crosslinking, which indicated that hydrogen bonding between imidazole rings became weak. In addition, GI WAXD revealed that the d-spacing of the crosslinked BS-PBI membrane was increased. Moreover, positron annihilation lifetime spectroscopy (PALS) clearly showed the structural change from monomodal curves (pore radius: 0.25-0.33 nm) to bimodal ones (pore radius: 0.15-0.25 nm and 0.25-0.38 nm) by crosslinking. The crosslinking-induced structural change, in particularly the partial formation of larger pores in the membranes, enhanced water permeability. Whereas, the selectivity of NaCl would be improved due to the formation of smaller pores. The introduction of crosslinked structure to the BS-PBI enhaced both the salt rejection and the water flux due to both the Donnan effect and the partially formation of smaller and larger pores in the membrane, respectively.

SnO₂ nanoparticles anchored on graphene oxide (flakes) (SnO₂-GO) were fabricated by electrodeposition using the rotating disk electrode technique. The composite was characterized by X-ray diffraction (XRD), Raman Spectroscopy, Fourier transform spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The samples show an interesting Photocatalytic behavior under ultraviolet irradiation. SnO₂-GO has fast and high photosensitivity response in comparison with SnO₂ nanoparticles alone. The presence of graphene contributes as an electron transporter of photogenerated charge carriers from tin dioxide nanoparticles. Methylene blue photo-degradation in the presence of the SnO₂ catalyst confirmed the effectiveness of this composite as photocatalyst. We exploited this property for the photoconversion of toxic NOx species in water into other environmentally friendly compounds.

Environmental protection is worldwide considered a primary issue of the sustainable development. In order to preserve our environment, a major challenge is to remedy the polluted environment by re-using wastes. In this work biowaste sourced soluble substances (CVT230) are used for the design of two types of heterogeneous photocatalysts for wastewater cleaning: an inorganic perovskite and a organic-inorganic hybrid. The materials were carefully characterized by XRD combined with Rietveld refinement, N₂ adsorption, FT-IR spectroscopy, thermo gravimetric analysis, transmission electron microscopy and zeta potential analysis. Their photocatalytic activity was tested for the abatement of pollutants found in wastewaters, 4-methylphenol (4-MP), a representative phenolic compound and/or the Crystal Violet (CV), a cationic dye. The experiments were performed in aqueous solution irradiated by simulated solar light.
The inorganic perovskite LaFeO₃ was prepared by solution combustion synthesis [1], where La and Fe metal nitrate precursors react with the fuel to start a heat-induced chemical chain reaction. CVT230 has the triple role of fuel, chelating agent and microstructural bio-template. The surfactant properties of CVT230 favor the formation of micelles which act as a pattern on which, after burning, LaFeO₃ with a porous structure is formed. The CVT230-derived LaFeO₃ showed a different photocatalytic behavior depending on the used substrate.
Recently, CVT230 was tested as homogenous photosensitizer for the degradation of chlorophenols [2]. In this study organic-inorganic hybridsCVT230/SiO₂ were obtained by grafting the CVT230 on different types of silica [3] both amorphous and with ordered mesopority (HMS and SBA-15), in order to have heterogeneous photocatalysts. The role of silica morphology and textural properties on the materials catalytic performance was thoroughly investigated.
The obtained results pointed out that the synthesis of both efficient photocatalysts LaFeO₃ and CVT230/SiO₂ hybrids may be obtained through sustainable processes, owing to the availability of cost-effective and environmentally compatible substances isolated from urban biowastes.
[1] F. Deganello, G. Marcigrave; and G. Deganello, J. Eur. Ceram. Soc., 2009, 29, 439-450.
[2] P. Avetta, F. Bella, A. Bianco Prevot, E. Laurenti, E. Montoneri, A. Arques and L. Carlos, ACS Sustainable Chem Eng., 2013, 1, 1545-1550.
[3] M.L. Testa, V. La Parola and A.M. Venezia, Catal. Today, 2014, 223, 115-121.

Graphene oxide (GO) is a very promising material because it is easy to process, water soluble, and chemically versatile due to the presence of oxygenated groups on its surface. Oxygenated groups like minus;COOH, minus;C=O, and minus;OH are important for the GO reactivity and for further functionalization. During preparation of GO sheets by exfoliating graphite with a mixture of potassium permanganate and concentrated sulfuric acid (modified Hummers method [1]), complex mixtures of highly oxidized polyaromatic carboxylated fragments minus; oxidative debris (OD) minus; are produced. While these debris, that are strongly bound to GO surface [2], act as surfactant and help stabilizing aqueous GO suspensions, they also change GO surface properties such as the capacity of adsorbing molecules by noncovalent functionalization. This capacity is specially important for remediating environmental pollutants. Here we study the role of OD on the GO capacity to adsorb organic pollutants. Single-layered GO was synthesized by a modified Hummers method (as-produced GO minus; aGO) and chemically treated to yield to debris-free GO (dfGO). We used the Salmonella typhimurium mutagenicity assay (Ames test [3]) to indirectly probe the GO adsorption capacity by looking at bacteria growth caused by non-adsorbed testing molecules (pollutants) on GO surfaces. We selected two important organic pollutants produced from incomplete combustion of fossil fuels (1-nitropyrene (1NP) and 3-nitrobenzanthrone (3NBA)) as the testing molecules. We observed that GO samples without oxidative debris were found to be 75% more effective to adsorb 1NP than samples with debris which indicates that OD reduce the GO adsorption capacity [4]. Molecular dynamics simulations indicated that the resulting weak interaction between 1NP and 3NBA molecules and aGO surfaces is not sufficient to trap these molecules. Our results suggest that OD with size comparable to the the size of 1NP and 3NBA molecules (~1 nm) are responsible for preventing adsorption sites on GO surfaces from being reached by potentially adsorbate molecules. We acknowledge the financial support from INOMAT, CNPq, CAPES and FAPESP.
References:
[1] W. S. Hummers and R. E. Offeman, J. Am. Chem. Soc. 80 (1958) 1339.
[2] J. P. Rourke, P. A. Pandey, J. J. Moore, M. Bates, I. A. Kinloch, R. J. Young, N. R. Wilson, Angew. Chem. 123 (2011) 3231-3235.
[3] K. Mortelmans and E. Zeiger, Mutat. Res. 455 (2000) 29-60.
[4] V. R. Coluci, D. S. T. Martinez, J. G. Honoacute;rio, A. F. de Faria, D. A. Morales, M. S. Skaf, O. L. Alves, G. A. Umbuzeiro, J. Phys. Chem. C 118 (2014) 2187minus;2193.

Solar to fuels (STF) constitutes one of the more promising emerging technologies for sustainable production of fuels from renewal energies as conversion energy efficiency can be assured to be, at least, higher than 10%. The direct conversion of the photon energies to the chemical one requires one absorber material, one photogenerated carrier separation capacity and one catalytic surface functionality for inducing oxidation (anode) or reduction (cathode) processes for obtaining hydrogen or C1 products respectively from the H2O or CO2 feed stocks.
A large list of materials have been suggested as absorbers based essentially on metal oxides or well know IV,III-V and chalcogenides semiconductors applied directly as electrode materials or taking part of a tandem structure.
In both cases, aside of the charge separation and bulk recombination rate the catalyst properties of the interface solid/electrolyte play one basic role for increasing the charge transfer rate from the absorber to the electrolyte which contributes to increase the overall efficiency of the energy conversion improving the energy balance of the overall photo electro chemical PEC cells.
In this contribution, different modifications of the electrode surface due to the presence of additives or alternatively to the use of electro catalysts (OER, HER) will be presented.
Surface characterization methods for determining the effective surface state density and profile will be shown and the role of the involved mechanisms related with the charge transfer rate between the solid electrode and the electrolyte will be exposed and modeled. Examples based on several metal oxides with different amount of additive for modifying their properties (TiO2, Fe2O3, WO3, hellip;) and semiconductor with different dopings will be shown and discussed. Likewise, the role of the self-potential oxidation and reduction will be taken into account and alternative options for protective passivation will also be reported in order to improve the sustainability -life time and use of critical material- as well as the overall conversion of solar energy to fuels, STF, efficiency.

Concentrated photovoltaic (CPV) systems have the potential to generate electricity at low cost with high conversion efficiency by replacing expensive photovoltaics with cheap optical elements. However, the principle of etandue conservation requires precise two-axis sun tracking for mid and high concentration systems. Reactive nonmechanical sun tracking has the potential to greatly expand the applicability and practicality of CPV by eliminating bulky moving parts and the requirement of precise active control. We present a nonmechanical solar tracker and concentrator that incorporates a receiving lens array and a concentrating waveguide whose receiving surface is an optical-switching material that becomes locally transparent when heated by a focused beam. In this way the switching material creates a moving aperture that tracks the position of the focused light spot, admitting most of the incident light into the waveguide while limiting optical losses. This design is realized using a thermal phase change material previously investigated for different applications. We discuss the engineering considerations involved in the optimization of the material performance as a movable aperture, optical and thermal characterization of the material, and simulation and preliminary experimental results for the performance of a prototype device.

Energy scenarios with aggressive carbon reduction goals have projected the increasing adoption of photovoltaics (PV) in future years. This rapid deployment of PV would require growth in the supply of materials that are used to manufacture these technologies. In this work, we estimate the growth rates of global metals production that would be needed to meet PV deployment targets put forward in aggressive low-carbon energy scenarios. We then compare the required growth rates to historical production trends for a large set of metals. We find that if crystalline silicon PV provides 25% of the electricity generation in 2030, the required growth in silicon production does not exceed 5% per year even at current material intensities. This growth rate is within the range of historical rates for metals production. In contrast, if cadmium telluride PV provides more than 1% of the projected electricity generation in 2030, tellurium production would need to grow at unprecedented rates unless there are dramatic decreases in material intensity.

Polycrystalline lead sulfide (PbS) quantum dots have been directly attached on single crystalline zinc oxide (ZnO) nanostructures (nanowires and nanowalls) to fabricate the building blocks of quantum dot sensitized solar cells (QDSSCs). ZnO nanowire arrays and ZnO nanowalls grown by pulsed laser deposition (PLD) were sensitized by PbS quantum dots (QDs) using the successive ionic layer adsorption and reaction (SILAR) synthesis technique.
Despite the advantages associated with QDSSCs through the use of different nanostructures (zero, one and two dimensional), tunable absorption of solar spectrum (UV-NIR), and multiple exciton generation, the electron transfer rate with minimum loss of photo-generated electrons remains a significant challenge.
Here we show the advantages of QDSSCs with the direct attachment of PbS QDs on ZnO nanostructures by a simple and easy technique without the use of organic ligands.

Essentially all methods of energy production—e.g., fracking, damming, drilling, nuclear fission, and excavation of rare-earth metals for photovoltaics—are associated with some degree of environmental degradation. Organic solar cells (OSCs) are regarded as low-cost and potentially environmentally benign sources of power. π-Conjugated (semiconducting) polymers—the components of OSCs responsible for absorbing light and transporting charge—are not typically synthesized in laboratories in ways that are amenable to manufacturing with low environmental impact. This article discusses strategies for producing conjugated polymers and transparent conductive electrodes using green chemistry and engineering. That is, processes with low energy intensity, with minimal production of toxic waste, and at low cost. This article briefly reviews the major findings in the literature on the energy intensity and carbon emissions associated with fabricating OSCs on the laboratory scale, and identifies several strategies and materials invented by the community to lower the cost and environmental impact of the components of the devices. The principles of green chemistry, applied to the synthesis of conjugated polymers, are identified as important guidelines for the multi-ton manufacturing of these materials. A general theme in both green chemistry and process research is that low cost can be correlated to environmental benignity when the costs of disposing wastes are high. This Perspective then highlights five synthetic strategies that satisfy several of the criteria of green chemistry: (1) polymerization using metal-mediated cross coupling reactions that reduce or eliminate stoichiometric organotin waste; (2) the use of heterogeneously catalyzed polymerizations; (3) polymerization involving activation of C-H bonds; (4) use of biofeedstock-derived starting materials; and (5) polycondensation reactions that evolve water as a byproduct. We also describe two new techniques for fabricating large-area transparent electrodes to replace indium tin oxide. The first method—abrasion lithography—uses a sharp tool to create furrows in a water-soluble film. The abraded film serves as a stencil mask for the deposition of grids of an inexpensive metal (e.g., copper), which is used as a transparent electrode in solar cells. The second method is a new technique of synthesizing high quality, single-layer graphene in a roll-to-roll compatible process using van der Waals forces. The process involves very little waste, in contrast to the conventional method for producing graphene over large areas, which destroys approximately 1,000 kg of copper foil for every 1 g of graphene that is produced.

Windows and glass facades often let in or out too much energy so that cooling or heating must be used in order to achieve a good indoor environment. Chromogenic fenestration can diminish the energy expenditure substantially by being able to adjust the transmittance of solar energy and visible light and is also able to improve indoor comfort. This paper outlines recent progress in thermochromics, which allows the transmittance to be lowered reversibly upon temperature increase, and in electrochromics which permits transmittance modulation between widely separated limits by the application of electrical voltage pulses. Thermochromics makes use of vanadium-dioxide-based thin films or nanoparticles; this technology has advanced strongly during the past few years and now appears viable for practical fenestration. Electrochromics is also under rapid development and the first products are currently on the market; they are normally based on thin films of nanoporous tungsten oxide and nickel oxide. Design of thermochromic and electrochromic devices, related materials, thin film deposition technology, and achievable performance limits are discussed in some detail.

We present prototypes of a new and unique class of thermochromic “motheye smart window” that exploits the material properties of vanadium dioxide to passively modulate the transmission of solar energy into a building. In addition, we will discuss the theoretical performance boundaries for a variety of vanadium dioxide smart window geometries.
The optical properties of vanadium dioxide are significantly enhanced when coated in thin layers over a nano-structured surface. Benchmarked against a planar geometry, maximum solar energy transmission modulation (the critical factor in assessing energy saving potential) is increased from 10% to almost 25% using this approach. This ranks the motheye geometry amongst the very highest performing VO₂ smart window classes.
Graded refractive index 'motheye' antireflection surface structures, inspired by nature, are chosen for both their optical and wetting enhancements. Our window surfaces are designed to efficiently transmit visible light over a wide range of angles (insensitive to the light&’s polarisation) whilst maintaining strong solar-thermal energy modulation, facilitating good energy saving. In addition, the high aspect ratio structures modify the hydrophobicity of the surface making it robustly super-hydrophobic which lends the window surface the ability to self-clean.
We will present our methods for fabricating the nano-structured glass surface using self-assembled colloidal lithographic methods. Optical and wetting performance tests of our devices will be presented and discussed.

The metal to insulator transition in vanadium dioxide (VO₂) exhibits a thermochromism with intriguing applications to ‘smart&’ building windows. Thermochromic VO₂ modulates its infrared transparency/reflectivity with ambient temperature. Above a critical transition temperature (i.e., on a “hot” day), VO₂-based materials have high reflectivity in the infrared, rejecting undesired solar heating, while at lower temperatures (i.e., a “cold” day) they are infrared transparent, utilizing the solar energy for heating. The transition temperature can be depressed from 68C in pure VO₂ by the incorporation of transition metal dopants. In this paper, we describe a combinatorial experiment designed to evaluate thermochromic transition temperatures in VO₂-based thin films. We use pulsed laser deposition (PLD) to prepare combinatorial thin film libraries of VO₂ + one or two other transition metal oxides in which the elemental composition varies continuously across the 3” diameter substrate; a single library can cover up to 50% of the binary or ternary composition space. Local composition is mapped by x-ray photoelectron spectroscopy (XPS) with a 1.5 mm² sample area. Thermochromism is mapped by measuring spectroscopic infrared reflectance at temperatures in the range of 15C to 85C. We find that < 10% of W, Nb, and Ta are effective at depressing the transition temperature to le; 30C, while exhibiting low thermal hysteresis and high switching. Higher dopant concentrations have deleterious effects on the thermochromic transition.

Global energy demand and consumption is steadily increasing causing not only energy shortages but also detrimental environmental pollution. One solution to the issue is to increase the production efficiency of the energy we already use. It has been proposed that by employing modest thermoelectric materials to collect otherwise wasted industrial heat or the heat from steam turbine engine, we can improve overall energy production efficiency by over 10%. The idea is highly intriguing and would go a long way toward more efficient energy production and meeting growing global needs. However, thermoelectric materials are currently still limited by two primary factors, one their energy conversion efficiency (zT value) is still low, and two, all of the best thermoelectric materials are composed of rare and/or toxic elements making them non-sustainable. In response we have begun to develop a new Cu-Zn-S (a chalcogenide material) nanoparticle system, which is made of abundant and non-toxic elements. For high efficiency, a thermoelectric material should be a good electrical conductor but a poor thermal conductor to have a high zT value. Thermal conductivity can be reduced by fabricating thermoelectric materials using those nanoparticles as building blocks with keeping their primary structure (i.e. nanograin). By employing advances in nanotechnology such as manipulation of the particle size, structure and composition, we can control the resulting thermoelectric properties. This presentation will focus on our latest results in the synthesis, characterization and study of the resulting thermoelectric properties for sustainable Cu-Zn-S nanoparticles. The results will be discussed using characterization techniques such as TEM, XRD, XPS, ICP, HAADF-STEM and others.

Thermoelectric materials can potentially find its application in the automobile industry, heavy manufacturing industries and places where large combustion engines operate continuously. Waste heat from automobiles, factories and similar sources offers a high-quality energy source equal to about 70% of the total primary energy, but it is difficult to reclaim because its sources are small and widely dispersed. Chalcopyrites material is notable for being highly sustainable as it is comprised of earth abundant and non-toxic elements. Nanoparticles of copper iron sulfide which is one of the typical chalcopyrites, has been synthesized using a bottom up wet chemical technique where composition can be manipulated by changing the metallic feeding ratio. Then we fabricated nanostructured copper iron sulfide thermoelectric materials using the nanoparticles as building blocks. The thermoelectric properties of nanostructured copper iron sulfide have not been extensively studied so far. The results will be discussed on the basis of synthetic approach, characterization of the materials and characterization of thermoelectric properties. The resulting nanoparticles will be characterized using techniques such as TEM, XRD, XPS, HAADF-STEM and others to map their physical and chemical properties.

Heterogeneous transition metal catalysts are generally based on nanoparticles, that nowadays can be synthesize with uniform size and shape. The extraordinary advances in material science support a new vision for nanoscale-inspired design and synthesis of industrially important catalysts. This precise structural and morphological control, coupled with the possibility to modulate the metal-support interactions, allowed us to have a step change increase in the activity, selectivity and stability of many industrially and environmentally important catalysts. In this context, renewable energy conversion, pollution prevention and control are the real challenge of the 21^st century and the focus of the present talk.
References:
Cargnello M.; Delgado Jaén J.J.; Hernández Garrido J.C.; Bakhmutsky K.; Montini T.; Calvino J.J.; Gorte R.J.; Fornasiero P., "Exceptional activity for methane combustion over modular Pd@CeO₂ subunits on functionalized Al₂O₃", Science 2012, 337, 713.
Chen Y.X.; Lavacchi A.; Chen S.P.; di Benedetto F.; Bevilacqua M.; Bianchini C.; Fornasiero P.; Innocenti M.; Marelli M.; Oberhauser W.; Sun S.G.; Vizza F. “Electrochemical milling and faceting (ECMF): a new method for size reduction and catalytic activation of palladium nanoparticles”, Angew. Chem. Int. Ed., 2012, 51, 8500.
Cargnello, M.; Doan-Nguyen, V.; Gordon, T.R.; Diaz, R.E.; Stach, E.A.; Gorte, R.J.; Fornasiero, P.; Murray, C.B., "Control of metal nanocrystal size reveals metal-support interface role for ceria catalysts.", Science 2013, 341, 771
Carraro, G.; Maccato, C.; Gasparotto, A.; Montini, T.; Turner, S.; Lebedev, O.I.; Gombac, V.; Adami, G.; Van Tendeloo, G.; Barreca, D.; Fornasiero, P. "Enhanced hydrogen production by photoreforming of renewable rxygenates through nanostructured Fe₂O₃ polymorphs", Adv. Funct. Mater. 2014, 24, 372.

Selective oxidation of alkali lignin yielding high-value chemical products is a priority of biomass reforming. Prior studies have found that alkali lignin reforming via sub- and supercritical water was effective at producing phenolic compounds.
The goal of this study was to identify the major trends towards selective oxidation of alkali lignin as a function of temperature and residence time in sub- and supercritical water. Liquefaction of alkali lignin was performed in a 316 SS vessel at 200, 300, and 400°C and residence times of 10, 30, 60, and 120 min at 3200 psi. Before bringing the vessel to the targeted T and P, alkali lignin (0.1g) was added to 6 mL of water.
The pressure vessel was connected to an ISCO syringe pump (Model 260D) filled with CO₂ with continuous monitoring of T and P. The liquid produced was centrifuged at 3500 rpm and filtered using Whatman 542 filter paper. The sediment was weighed to determine the percent liquefaction and the organic compounds were separated from the water by solid phase extraction. The organic compounds were analyzed and identified via a Hewlett Packard 5890 Series II gas chromatograph and HP5970 Series mass spectrometer.
The major trends in the formation of the products during hydrothermal liquifaction were identified. The results demonstrate that in all tests a high amount of guaiacol was produced. The higher yields (76.83%) occurred at the lower temperatures (200-300°C) corresponding to the sub-critical water environment (residence time 1 hr). At higher temperatures (400°C) and increasing residence times, guaiacol&’s yield was reduced but the yield of both phenol (15.8%) and catechol (17.08%) was increased; this indicates that the guaiacol may be converted to phenol and catechol at higher temperatures. Other compounds (e.g. vanillin and homovanillic acid) appear in yields > 20%, while a large number of additional byproducts of lignin are produced < 5% - 10%. Many of these compounds demonstrate trends of increasing or decreasing yield vs. residence time and T, indicating the importance of these two parameters for selective synthesis of benzene -based derivatives in sub- or supercritical water.
It has been shown [1] that the presence of organic solvents in sub- and supercritical water increases the liquefaction of lignin, by preventing the re-polymerization of the low molecular weight products. The main trends of the lignin decomposition in solvent-free and catalyst-free environments will be compared to the results obtained for water-organic solvent (e.g. 1-butanol) mixtures at the same T, P, and residence times. The results regarding catalyst-free liquifaction of lignin in presence of various solvents will be presented and discussed in terms of selectivity and chemical mechanisms of lignin decomposition.
[1] T. Yoshikawa, et al., Production of phenols from lignin-derived slurry liquid using iron oxide catalyst. Appl. Catal. B: Environ.(2014), Volume 146, 289-297.

In the past years, enzymes (natural and biodegradable catalysts) have become a central part in green chemistry in order to reduce the use of chemical routes for synthesis of common chemical products. Apart from the high product quality the use of enzymes is accompanied by lower manufacturing costs, less toxic waste disposal and reduced energy consumption which stimulates growth of sustainable societies by utilizing biochemical pathways that already exist in nature [1]. In most large-scale biocatalytic processes however, enzymes are immobilized in order to improve the recycling, continuous use as well as the thermal and pH stability [2, 3]. The recent synthesis of magnetic nanocomposites opened new possibilities in biocatalysis and enzymes have been immobilized on different magnetic supports (mainly iron oxide). However, the inability of the current magnetic carriers to be efficiently recycled from large volumes (lower magnetic saturation) impedes their further usage in industrial processes. The development of a core/shell-enzyme nanomaterial with a very high magnetic saturation (> 150 emu/g) enables us to efficiently perform magnetic biocatalysis and very quickly (< 30 s) separate the enzyme from solution in large volumes (15 L) by a custom made magnetic separator. Such small and magnetically separable catalysts combine the advantages of easy and fast separation with high dispersion and reactivity [4].
In this study Co/C nanoparticles were chemically functionalized (diazonium chemistry), activated for bioconjugation (N, N-Disuccinimidyl carbonate) and subsequently used in enzyme immobilization [5]. Three enzymes: β-glucosidase, α-chymotrypsin and lipase B were successfully covalently immobilized on the magnetic nanosupport. The enzymes on particles retained up to 55 % enzymatic activity after immobilization compared to the free enzymes in solution. In addition the immobilized enzymes showed improved storage stabilities and were efficiently recycled from millilitre to litre scales in short recycle times.
[1] - M. Alcalde, M. Ferrer, F. J. Plou, A. Ballesteros, Trends Biotechnol 2006, 24,6
[2] - J. Kim, J. W. Grate, P. Wang, Chem. Eng. Sci. 2006, 61, 1017 - 1026
[3] - U. T. Bornscheuer Angew. Chem. Int. Ed.2003, 28, 42(29):3336-7
[4] - A.H. Lu, E.L. Salabas, F. Schüth Angew. Chem. Int. Ed. 2007, 46; 1222 - 1244
[5] - V. Zlateski, R. Fuhrer, F.M. Koehler, S. Wharry, M. Zeltner, W.J. Stark, T.S. Moody and R.N. Grass Bioconjugate Chem. 2014, 25. 677-684

Over recent decades there has been an increase in the study of catalysts for the carbon dioxide (dry) reforming of methane (DRM). The ability for the DRM reaction to consume two of the most destructive greenhouse gases, methane and carbon dioxide, for the production of synthesis gas (an intermediary for the production of synthetic diesel and methanol) makes it a highly desirable process for future research. Additionally, with the depletion of natural gas, the DRM has the ability to utilise sustainable biogas as a CH₄ source without CO₂ removal. Although highly desirable from an environmental perspective, the implementation of DRM catalysts on an industrial scale is limited by cost and stability. Reduction-oxidation-reduction (ROR) pre-treatment has been suggested as strategy for enhancing the activity and stability of supported metal catalysts by reducing active metal deposit size and altering metal support interaction, although it is yet to be studied for the DRM.
The impact of ROR pre-treatment on Ni-SiO₂ catalysts for the DRM was studied at a variety of Ni loadings (5, 7.5 and 10% wt.). Samples were reduced in 50% H₂/Ar at 350^oC for 10 h, oxidised in air at 300^oC for 2 h and subsequently re-reduced in 50% H₂/Ar at 275^oC for 10 h. X-ray diffraction, transmission electron microscopy and hydrogen temperature programmed reduction demonstrated that ROR pre-treatment decreased the average Ni size and altered the interaction between the Ni and SiO₂, which significantly impacted the catalytic performance. ROR pre-treatment resulted in an increase in CH₄ conversion, most significantly for the 10% Ni-SiO₂ samples (from 57% to 69% at 800°C) with comparable carbon formation between the reduced and ROR pre-treated samples. At lower temperatures (600°C) the reduced samples deactivated, due to carbon build-up, after 3-4 h reaction time. On the other hand, the ROR samples maintained stable conversion after 6h over a 12h time frame. Additionally, for all samples (500-800°C), ROR pre-treatment resulted in a more stoichiometric H₂/CO ratio. ROR pre-treatment provides a simple and inexpensive means of improving DRM catalysts, which can be pre-treated in-situ in reaction conditions with the use of air and hydrogen.

The design of new functional nanomaterials for enhancing oxygen reduction reaction (ORR) is highly desirable for promoting the development of fuel cell and lithium air battery devices. In this seminar, I will focus on my recent advances in rational design and controlled synthesis of high-quality multicomponent nanocrystals for enhancing ORR. I will start with three examples on how to engineer FePt NWs, FePtPd/FePt core/shell NWs and graphene-FePt NPs composite for getting advanced Pt-based catalysts for ORR with extremely high activity and stability. After that, I will move to non-Pt catalysts such as graphene-Co/CoO NPs and M/CuPd NPs (M=Ag, Au), which exhibit comparable and even higher ORR activity and stability than commercial Pt catalyst.

Biomass conversion to renewable chemicals and fuels has received significant attention as a means to the sustainable society. Among all forms of biomass available, cellulose is considered the most suitable for biofuel and green chemical production because of its abundance resources which is not included in the human food chain. However, the efficient chemical transformation of cellulose has remained a challenge according to its persistent property. Here, cellulose was selectively converted into sugar alcohol (sorbital) over supported-metal catalysts by the application of plasma in the cellulose aqueous suspension. Generally, conversion of cellulose to sugar alcohol should be done under H₂ pressure and high temperature. The goal of using solution plasma process is to initiate self-hydrogenation by reactive hydrogen species generated from the plasma due to dissociation of water. Effect of the pre-treatment process of the cellulose on the catalytic conversion of cellulose into sugar alcohols was investigated.

Ceria-zirconia mixed oxides are key materials both as catalysts and as catalyst supports of noble metal nanoparticles, for a variety of chemical processes related to Environmental Catalysis. It is widely accepted that one of the key properties of ceria-zirconia oxides in their role as catalysts or catalyst supports is their ability to exchange lattice oxygen with reactants, usually referred to as Oxygen Storage Capacity (OSC). Such capacity is coupled to the Ce⁴⁺/Ce³⁺ redox exchange, i.e. to the reducibility of the oxide, which is dependent on a number of textural, structural and compositional factors. These factors are not independent but, instead, they are intimately related to each other and connected through thermochemical treatments. Disentangling the complex relationships existing between them has been the focus of a very intense research which has finally led to a model which rationalizes the relationships existing between redox performance, nanostructure and pretreatment conditions.
However, access to Rare Earth Elements (REE) and Platinum Group Metals (PGMs) is nowadays considered a major limiting factor for the development of Green Technologies, a quite relevant aspect from both economic and geo-strategic points of view. Thus, low lanthanide contents and a noble-metal free formulation have become a topic in which an impact of current research is expected.
Taking into account the basic scientific knowledge, particularly that related to the key role of the surface structure of these oxides, our strategy relies on synthesizing new materials which incorporate ceria (CeO₂) as nanometer thick surface layers coherently grown onto the surface of a carrier oxide (ZrO₂, YSZ). The analysis of the Redox properties of this new type of catalysts, which play in fact a key role in their catalytic performance in a variety of reactions, indicates a large improvement with respect to materials based on bulk ceria. A better performance is observed both in H₂-reducibility at low temperatures as well as in the stability of the redox response against aging treatments at very high temperatures.
Electron microscopy analysis of these new materials has been key both to check the success in the nanostructuration targets proposed for their synthesis and indeed, more important, to understand the behavior observed at macroscopic level in their redox properties. Summarizing, these materials not only mimic but also surpass the redox performance of noble metal loaded catalysts based on bulk ceria-zirconia mixed oxides emphasize a more efficient usage of ceria in terms of redox exchange capacity.

Decreasing the emission carbon dioxide (CO₂) into atmosphere is one of most important issues for human society to develop the sustainable environment. Electrochemical reduction of CO₂ has received considerable attraction. It is considered as a potential method to develop the sustainable energy conversion, to reduce the CO₂ emission, and to increase the efficiency of consumed energy. Previous studies have investigated metal catalysts as electrochemical heterogeneous catalysts to convert CO₂ highly efficiently to fuel products with high economic values, such as methane, ethane, formate and carbon monoxide.^[1] However, high overpotential and therefore high energy input are needed to electrochemically reduce CO₂, because high energy barriers between the reactant CO₂ and the chemical fuel products. Kanan&’s group has recently developed the oxide-derived metal to successfully decrease the overpotential.^[2] Rosen&’s group has found out nano-porous silver as electrocatalysts with lower overpotential, higher current efficiency and current density.^[3]
In this work we use chloride-derived silver as electrocatalysts for CO₂ reduction. By modifying the surface morphology and composition of silver metal using chloride, the reduction CO₂ to CO current efficiency is increased to 84%, compared to 2% for pure silver metal at -0.6 V (vs. reversible hydrogen electrode, RHE), and the CO partial current density is 190 times of that for pure silver. The changes of surface morphology for the chloride-derived silver before and after catalytic reaction are studied by scanning electron microscopy (SEM). The roles of chloride and silver to the reaction are investigated by X-ray photon spectroscopy (XPS). Our study opens up new strategies to design catalysts with enhanced catalytic performance for CO₂ reduction and other sustainable development by modifying the structure and thus the properties of materials.
[1] Hori, Y. Modern aspects of electrochemistry. Springer New York, 2008. 89-189.
[2] Li, C. W., & Kanan, M. W. J. Am. Chem. Soc. (2012), 134(17), 7231.
[3] Lu, Q., et al.. Nature Communications (2014), 5, 3242.

Catalysis is becoming a strategic field of science because it represents a new way to meet the challenges of energy and sustainability. Gold has attracted wide interest as a catalyst in the past few years because of its unexpected activity and especially its high selectivity in organic reactions.[1-2] The catalytic properties of gold depend on several factors such as gold particle size and morphology, metal-oxide support interaction, oxidation state of the active sites and so on.[3-4] To avoid aggregation, gold clusters are usually stabilized using thiols or phosphines ligands that strongly decrease their catalytic activity highlighting the importance to obtain stable gold clusters ligand free. Although it appears that to control reactivity the atomicity control of the gold clusters is crucial, the synthesis of size-selected metal clusters and their deposition over a solid support for their recovery and prevent cluster agglomeration is a challenging task.[5]
In this work magnetically recoverable Au clusters supported on a core-shell Fe₃O₄@SiO₂ nanoparticles were synthesized using a two steps procedure. In the first step the Fe₃O₄ nanoparticles and the water soluble porphyrin 5,10,15,20-Tetrakis(4-trimethylammoniophenyl)porphyrin tetra(p-toluenesulfonate) (TTMAPP) were encapsulated inside SiO₂ nanoparticles using a reverse micro-emulsion method.[6] In the second step, the purified Fe₃O₄@SiO₂ nanoparticles were redispersed in methanol and mixed with HAuCl₄ to synthesize the Au clusters immobilized on the surface of the Fe₃O₄@SiO₂ nanoparticles. The redox reaction between the TTMAPP and HAuCl₄ gave an homogenous distribution of gold clusters with an average size of 1.3 ± 0.4 nm and they were thiol or phosphine ligand free. The Fe₃O₄@SiO₂@Au nanoparticles were used as catalyst to study the reduction of 4-nitrophenol to 4-aminophenol by sodium boronhydride and they gave a turnover frequencies 1000 times faster than Au clusters stabilized with thiols or phosphines.[7-8]
References
1)Haruta, M.; Kobayashi, T.; Samo, H.; Yamada, N. Chem. Lett. 1987, 405-408.
2) M. D. Hughes, Y.-J. Xu, P. Jenkins, P. McMorn, P. Landon, D. I. Enache, A. F. Carley, G. A. Attard, G. J. Hutchings, F. King, E. H. Stitt, P. Johnston, K. Griffin, C. J. Kiely, Nature 2005, 437, 1132-1135.
3) Hutchings, G. J. Catal. Today 2005, 100, 55-61.
4) Chen, M. S. & Goodman, D. W. Acc. Chem. Res. 2006, 39, 739-746.
5) Jia, C. J. & Schuacute;th, F. Phys. Chem. Chem. Phys. 2011, 13, 2457-2487.
6) D.thinsp;K. Yi, S.thinsp;T. Selvan, S.thinsp;S. Lee, G.thinsp;C. Papaefthymiou, D. Kundaliya, J.thinsp;Y. Ying, J. Am. Chem. Soc. 2005, 127, 4990-4991
7) Stratakis, M.; Garcia, H. Chem. Rev. 2012, 112, 4469-4500.
8) Shivhare, A.;Ambrose,S. J.;Zhang, H.; Purves, R.W.;Scot,R.W. J. Chem. Commun. 2013, 49, 276-278.

Platinum group transition metals are among the most efficient CO₂
conversion catalysts known [1], but suffer from CO poisoning due to
their large CO binding energy of around 1.5 eV. Additionally, platinum
catalysts also catalyze the competing hydrogen evolution reaction (HER),
and their high cost prevents scalability. Here we demonstrate with
first-principles calculations, i.e., DFT using the RPBE functional, that
doped tungsten carbide (WC) can be an inexpensive and more efficient
alternative.
We systematically screened a large number of transition metal dopants
(e.g. Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Ir, Pt and Au) to
identify compositions with decreased binding energies of the reaction
intermediates (such as CO, COH, COOH, and H), but with equivalent or
superior CO₂ activation. The trends among the transition metals can be
understood in terms of the electronic structure. Our results can suit as
a guideline for the synthesis of improved CO₂ conversion catalysts [2].
We also investigated energetic details of the reaction mechanism of CO₂
reduction on WC surfaces. Unlike metal surfaces, the protonation of CO*
to form CHO* is exergonic because of the oxophilic characteristic of
metal carbide surfaces. As a result, O* and OH* are strongly bound to
the surface at the end of the reaction. To avoid the strong O* binding,
we investigated the effect of transition metal doping to change the WC
surface electronic structure. The results of this screening demonstrate
that the O* and OH* binding energies can be reduced while the CHO* still
bound to the surface strongly, and hence indicate that this approach
could be useful for finding a low-cost catalyst for the CO₂ reduction
[3].
[1] C. Shi, CP. O'Grady, A. Peterson, HA. Hansen, JK. Noslash;rskov, Phys. Chem. Chem. Phys., 2013,15, 7114.
[2] Wannakao et al. in preparation 2014.
[3] Wannakao et al. in preparation 2014.