Multiple and Nonlocal Cation Redox in Ca-Ce-Ti-Mn Oxide Perovskites for Solar Thermochemical Applications

Robert Wexler, Gopalakrishnan Sai Gautam, Robert Bell, Sarah Shulda, Nicholas Strange, Jamie Trindell, Joshua Sugar, Eli Nygren, Sami Sainio, Anthony McDaniel, David Ginley, Emily Carter, Ellen Stechel

Research output: Contribution to journalArticlepeer-review

4 Scopus Citations

Abstract

Modeling-driven design of redox-active off-stoichiometric oxides for solar thermochemical H2 production (STCH) seldom has resulted in empirical demonstration of competitive materials. We report the theoretical prediction and experimental evidence that the perovskite Ca2/3Ce1/3Ti1/3Mn2/3O3 is synthesizable with high phase purity, stable, and has desirable redox thermodynamics for STCH, with a predicted average neutral oxygen vacancy (VO) formation energy, Ev = 3.30 eV. Flow reactor experiments suggest potentially comparable or greater H2 production capacity than recent promising Sr-La-Mn-Al and Ba-Ce-Mn metal oxide perovskites. Utilizing quantum-based modeling of a solid solution on both A and B sub-lattices, we predict the impact of nearest-neighbor composition on Ev and determine that A-site Ce4+ reduction dominates the redox-activity of Ca2/3Ce1/3Ti1/3Mn2/3O3. X-ray absorption spectroscopy measurements provide evidence that supports these predictions and reversible Ce4+-to-Ce3+ reduction. Our models predict that Ce4+ reduces even when it is not nearest-neighbor to the VO, suggesting that refinement of Ce stoichiometry has the possibility of further enhancing performance.

Original languageAmerican English
Pages (from-to)2550-2560
Number of pages11
JournalEnergy and Environmental Science
Volume16
Issue number6
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 The Royal Society of Chemistry.

NREL Publication Number

  • NREL/JA-5900-83538

Keywords

  • computational modeling
  • STCH
  • water splitting
  • XAS

Fingerprint

Dive into the research topics of 'Multiple and Nonlocal Cation Redox in Ca-Ce-Ti-Mn Oxide Perovskites for Solar Thermochemical Applications'. Together they form a unique fingerprint.

Cite this