Bimetal synergistically regulates Ni and P oxidation states for efficient oxygen evolution reaction

Abstract

Developing a high-performance and low-cost precious metal-free catalyst for the oxygen evolution reaction (OER) is key to solving the problem of hydrogen production via water electrolysis, but it is still faced with low energy efficiency due to slow dynamics. Herein, we report a novel and efficient (Fe,Mn)Ni₂P-ECO electrocatalyst for the OER through artificially regulated reconstruction of the as-prepared Ni₂P by controlled electrochemical oxidation in an electrolyte containing Fe and Mn ions. The synergistic effect between Fe and Mn effectively promoted the formation of Ni and P oxidation states, reduced the Gibbs free energy of the rate-limiting step, and promoted the formation of the *O intermediate species. As a consequence, the developed (Fe,Mn)Ni₂P-ECO shows excellent OER electrocatalytic performance with an overpotential of 207 mV at 10 mA cm⁻² and 100 h stability at 20 mA cm⁻². This work provides an effective strategy for designing efficient nonprecious metal OER catalysts for water electrolysis.