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A Fundamental Relationship between Reaction Mechanism and Stability in Metal Oxide Catalysts for Oxygen Evolution

2016; American Chemical Society; Volume: 6; Issue: 2 Linguagem: Inglês

10.1021/acscatal.5b02432

2155-5435

Rong Xi, Jules Parolin, Alexie M. Kolpak,

Catalytic Processes in Materials Science

Rational design of efficient, stable oxygen evolution reaction (OER) catalysts is necessary for widespread adoption of electrochemical energy storage technologies. Achieving this goal requires elucidation of fundamental relationships between surface structure and reaction mechanism. Here we address this issue using ab initio computations to determine the surface structure and OER mechanism for LaNiO3, a perovksite oxide that exhibits high activity but low stability. We find a new OER mechanism in which lattice oxygen participation via reversible formation of surface oxygen vacancies is critical. We show that this mechanism has a lower reaction barrier compared to the generally proposed mechanism, leading to improved agreement with experimental data. Extending the study to La1–xSrxBO3 (B = transition metal), we demonstrate a transition to the lattice oxygen-mediated mechanism with decreasing catalyst stability. Our results suggest new approaches for next-generation catalysts design.