Itinerant Spins and Bond Lengths in Oxide Electrocatalysts for Oxygen Evolution and Reduction Reactions

Thorough analyses of structural factors in catalysis are interesting because they allow the massive prescreening of potential optimum compositions. Overall, this article shows how the orbital physics of magnetic compositions relates with spin–lattice interactions and then band gaps and bond lengths together become relevant descriptors in catalytic oxygen technologies. Active electrocatalysts for the oxygen evolution reaction (OER) include magnetic oxides with metals at relatively high oxidation states, so chemisorbed molecular O2 is not very stable. On the other hand, ideal compositions for the oxygen reduction reaction (ORR) have metals in a comparatively lower oxidation state, which can supply electrons to activate O2 molecules toward electron-richer oxygen atoms. Spin–lattice interactions in these strongly correlated oxides relate the orbital configurations and oxidation state with distinctive metal–oxygen bond distances, indicating localized or itinerant electronic behavior and selectivity in oxygen e...