Systematic Study of Descriptors for Oxygen Evolution Reaction Catalysis in Perovskite Oxides

Ever-proposed descriptors of catalytic activity for the oxygen evolution reaction (OER) were systematically investigated. A wide variety of stoichiometric perovskite oxides ABO 3 (A = Ca, Sr, Y, La; B = Ti, V, Cr, Mn, Fe, Co, Ni, Cu) were examined as OER catalysts. The simplest descriptor, e g, electron number of transition-metal ions at the B-site, was not applicable for OER overpotentials (η) of the compounds tested in this study. Another descriptor, oxygen 2p band center relative to Fermi energy (ε 2p ), was not necessarily adequate for the most part of perovskite oxides. Eventually, a recently proposed descriptor, charge-transfer energy (Δ), displayed a linear relationship with η most reasonably. Because Δ values were obtained from theoretical calculations, not only by spectroscopic experiments, systematic exploration for a wide range of compounds including hypothetical ones could be allowed. This finding proposes the charge-transfer energy as the most helpful descriptor for the design of perovskite oxide catalysts for the OER.