Available on-demand - *S.CT08.03.04
The Diverse and Complex Nonclassical Pathways of Nanoporous Aluminosilicate Crystallization
University of Houston1
The unique properties of nanoporous aluminosilicates (zeolites) are exploited in a variety of applications spanning from ion exchange and separations to catalysis and drug delivery. The ability to selectively control zeolite synthesis to achieve desired physicochemical properties relies upon detailed understandings of the thermodynamic and kinetic factors regulating crystal nucleation and growth, which are generally lacking. Designing innovative approaches to tailor zeolite crystallization and elucidate structure-performance relationships has the potential to produce materials with superior properties beyond what is achievable by conventional routes. In this talk, I will discuss efforts to characterize the complex mechanisms of zeolite crystallization, which occur by nonclassical pathways1-2 involving the self-assembly and structural evolution of amorphous precursors.3-5 There is still much that we do not understood regarding the role of precursors in nucleation6 and the influence of growth conditions on the selection of crystal topology,7 which underscores the need for molecular-level studies of zeolite crystallization. Our group addresses these challenges using a broad range of techniques that include the use solvothermal atomic force microscopy to capture time-resolved images of growing zeolite surfaces in real time.8 This technique has led to the first in situ characterization of zeolite growth with the capability of resolving surface dynamics at the spatiotemporal scales necessary to elucidate mechanistic pathways of crystallization. Based on our findings, we observe that growth occurs via multiple (cooperative) pathways that differ from one material to the next. In this talk, we will summarize our findings for several zeolite structures.
1. De Yoreo, J. J.; Gilbert, P.; Sommerdijk, N.; Penn, R. L.; Whitelam, S.; Joester, D.; Zhang, H. Z.; Rimer, J. D.; Navrotsky, A.; Banfield, J. F.; Wallace, A. F.; Michel, F. M.; Meldrum, F. C.; Colfen, H.; Dove, P. M., Crystallization by particle attachment in synthetic, biogenic, and geologic environments. Science 2015, 349 (6247), 498-+.
2. Kumar, M.; Choudhary, M. K.; Rimer, J. D., Transient modes of zeolite surface growth from 3D gel-like islands to 2D single layers. Nat. Commun. 2018, 9, 2129 (1-9).
3. Kumar, M.; Li, R.; Rimer, J. D., Assembly and Evolution of Amorphous Precursors in Zeolite L Crystallization. Chem. Mat. 2016, 28 (6), 1714-1727.
4. Oleksiak, M. D.; Soltis, J. A.; Conato, M. T.; Penn, R. L.; Rimer, J. D., Nucleation of FAU and LTA Zeolites from Heterogeneous Aluminosilicate Precursors. Chem. Mat. 2016, 28 (14), 4906-4916.
5. Kumar, M.; Luo, H.; Roman-Leshkov, Y.; Rimer, J. D., SSZ-13 Crystallization by Particle Attachment and Deterministic Pathways to Crystal Size Control. J. Am. Chem. Soc. 2015, 137 (40), 13007-13017.
6. Rimer, J. D.; Tsapatsis, M., Nucleation of open framework materials: Navigating the voids. MRS Bull. 2016, 41 (5), 393-398.
7. Maldonado, M.; Oleksiak, M. D.; Chinta, S.; Rimer, J. D., Controlling Crystal Polymorphism in Organic-Free Synthesis of Na-Zeolites. J. Am. Chem. Soc. 2013, 135 (7), 2641-2652.
8. Lupulescu, A. I.; Rimer, J. D., In Situ Imaging of Silicalite-1 Surface Growth Reveals the Mechanism of Crystallization. Science 2014, 344 (6185), 729-732.