Elucidation of the Electrocatalytic Function of Composite Metal Carbides Co₃W₃C and Co₃Mo₃C with Oxygen Reduction and Oxygen Evolution Reactions

抄録

Metal-air secondary batteries have attracted attention as a next-generation energy storage system due to their high energy density and environmentally friendly characteristics. However, it is important to develop a catalyst that can rapidly promote both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). We have found that Co₃W₃C and Co₃Mo₃C composite metal carbides prepared by a wet method have high bifunctional electrode performance, but the mechanism of action has not been elucidated. In this study, we comprehensively evaluated the adsorption behavior of oxygen molecules and surface hydroxyl groups, the charge density difference, and the effects of surface structure and chemical composition on catalytic activity by combining DFT (density functional theory) calculations and instrumental analysis. In particular, we found that Co₃Mo₃C optimizes the adsorption of oxygen molecules by metal compositing, contributing to the improvement of electrode catalytic performance.