Hirai H, Jinnouchi R. Mechanisms of temperature-dependent oxygen absorption/release and appearance of intermediate phase in κ-Ce
2Zr
2O
8: study based on oxygen vacancy formation energy computations.
RSC Adv 2022;
12:16717-16722. [PMID:
35754917 PMCID:
PMC9169551 DOI:
10.1039/d2ra02419e]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/30/2022] [Indexed: 12/03/2022] Open
Abstract
This study clarified the mechanisms of the temperature-dependent oxygen absorption/release properties and appearance of the intermediate phase for κ-Ce2Zr2O8, which is known to have a high oxygen storage/release capacity (OSC). First-principle computations revealed that the vacancy formation energies depend on the number of vacancies and can be categorized into two groups: low-energy and high-energy. The intermediate phase observed experimentally was assigned to the state after all the oxygen vacancies in the low-energy group were formed. We also found that the mechanism of the improved OSC performance by Ti substitution could be explained in terms of the vacancy formation energies.
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