Ni–Fe synergic effect in Fe–NiOHx boosting oxygen evolution under large current density enabled by the “in situ self-corrosion” strategy

Abstract

NiFe-based electrode materials have been reported as a promising candidate for the oxygen evolution reaction (OER). However, fabrication of such electrode materials with both high catalytic activity and long-term stability remains challenging. Herein, we developed an in situ self-corrosion photodeposition method to synthesize a self-standing hollow Fe–NiOH_x catalyst on photoactive ZnO nanorods. The stable phase of the catalyst and the excellent adhesion interaction with the substrate brings excellent electrochemical stability. The synergetic effect between Ni and Fe atoms significantly enhances the adsorption of the OH group and facilitates the removal of the surface H atom, leading to lower overpotential. As a result, the as-fabricated catalyst exhibits excellent OER activity and remarkable stability at a high current density, which only requires an overpotential of 210 mV at a current density of 10 mA cm⁻² and shows no significant degradation after a 240-h durability test at a high current density of 100 mA cm⁻². This research work provides an alternative approach for the rational design of desirable electrocatalysts with high activity and long-term stability.