Self-templated fabrication of P-doped CoMoO₄-Co₃O₄ hollow nanocages for the efficient oxygen evolution reaction

Finding reservoir-rich and efficient electrocatalysts for the alkaline oxygen evolution reaction (OER) is crucial for further sustainable energy development. Despite the advantages of high earth abundance, easy availability, and tunable composition, transition-metal oxides are typically considered poor electrocatalysts for the OER. In this study, a composite P-doped CoMoO₄-Co₃O₄ hollow nanocage is deliberately synthesized through a cation-exchange, pyrolysis, and phosphorization approach using an innovative self-template strategy with ZIF-67 as the sacrificial template. Hollow nanocages provide large surface areas and abundant active sites, enhancing electron transfer. Hybridization with other components increases the number of electrochemically reactive sites and optimizes the advantages of different element components. As a result, the P-CoMoO₄-Co₃O₄ hollow nanocage catalyst demonstrates high OER performance, with an overpotential of 279 mV at a current density of 10 mA cm^-2. Additionally, P-CoMoO₄-Co₃O₄ catalysts exhibit good dispersibility and excellent long-term stability. Experimental findings and density functional theory (DFT) calculations indicate that the phosphorus-doping effect in various aspects contributes significantly to the superior catalytic activity of P-CoMoO₄-Co₃O₄. This work provides a valuable method for designing cost-effective P doped Co-based bimetal oxide catalysts with outstanding OER performance for industrial applications.