9:40 PM - EN05.05.03
Late News: Solar Thermochemical Hydrogen Production on Layered Perovskite BaX0.25Mn0.75O3 (X = Ce, Nb, Pr) and BaTi0.5Mn0.5O3
James Park1,Eric Coker1,Mark Rodriguez1,Andrea Ambrosini1,Anthony McDaniel1
Sandia National Laboratories1
Solar thermochemical hydrogen production (STCH) is a two-step process that utilizes concentrated solar heat and metal oxide materials to produce hydrogen gas by splitting water molecules through oxide redox chemistry. Among the many different materials investigated, perovskite (ABO3) materials, including SrxLa1-xMnyAl1-yO3 (x, y = 0.4, 0.6)1 and ATi0.5Mn0.5O3 (A = Ca and Sr),2,3 have been reported that are competitive with CeO2, the current benchmark material. Multiple combinations of perovskite-like materials are possible with diverse crystal structures due to partial cation substitution and vacancy formation on the metal and oxygen sites, which influence the electronic structure and consequent STCH performance. Recently, BaCe0.25Mn0.75O3 (BCM), a layered perovskite, was shown to have faster water oxidation kinetics than SrxLa1-xMnyAl1-yO3 (x, y = 0.4, 0.6) and better hydrogen production capability than ceria at a lower thermal reduction temperature (TR=1350 °C).4 In the course of determining the chemical underpinnings of BCM’s performance, three new water-splitting and isostructural materials, BaNb0.25Mn0.75O3 (BNM), BaPr0.25Mn0.75O3 (BPM), and BaTi0.5Mn0.5O3 (BTM), were synthesized and characterized. Comparing the performance and structural changes of these materials in operando aids in the understanding of the relationship between hydrogen production capability and the different local environments of the metal-oxygen bonds resulting from the chemical modification. From this, a better fundamental understanding can be developed to aid in identifying new materials for solar thermochemical fuel production.
1. McDaniel, A. H.; Miller, E. C.; Arifin, D.; Ambrosini, A.; Coker, E. N.; O'Hayre, R.; Chueh, W. C.; Tong, J. Energy Environ. Sci. 2013, 6, 2424.
2. Qian, X.; He, J.; Mastronardo, E.; Baldassarri, B.; Yuan, W.; Wolverton, C.; Haile, S. M. Matter 2020, 4, 1.
3. Qian, X.; He, J.; Mastronardo, E.; Baldassarri, B.; Wolverton, C.; Haile, S. M. Chem. Mater. 2020, 32, 9335.
4. Barcellos, D. R.; Sanders, M. D.; Tong, J.; McDaniel, A. H.; O’Hayre, R. P. Energy Environ. Sci. 2018, 11, 3256.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. The views expressed in this article do not necessarily represent the views of the U.S. Department of Energy or the United States Government.