Calculated Descriptors of Catalytic Activity for Water Electrolysis Anode: Application to Delafossite Oxides

Understanding the oxygen evolution reaction (OER) is crucial for improving the performance of water electrolysis. Copper delafossite oxides (CuBO 2, B = transition metal) were investigated for their potential as OER catalysts using density functional theory (DFT) calculations. To identify an appropriate descriptor for OER activity, we examined the relationships between the calculated e g or t 2g occupancy of the B site and the experimentally determined OER activity. The calculated t 2g occupancy was found to be approximately linearly related to OER activity. We therefore propose that t 2g occupancy can be employed as an appropriate descriptor of the OER activity of delafossite oxide catalysts. The d-electron occupancy of active sites, estimated using theoretical calculations, can be used to search efficiently for transition metal oxide catalysts with high OER activity.