Controlled phosphating: a novel strategy toward NiP3@CeO2 interface engineering for efficient oxygen evolution electrocatalysis

Abstract

Although Ni phosphides are efficient for hydrogen evolution reactions, they are unfavorable for oxygen evolution reactions, so their application in alkaline water electrolysis is limited. It is a feasible method for creating a novel Ni phosphide/oxide heterogeneous interface to promote the oxygen evolution kinetics of Ni phosphide materials in an alkaline medium, yet it has been an unprecedented challenge for researchers. In this work, NiP₃@CeO₂ hybrid nanoparticles are firstly in situ grown on Ni foam (NiP₃@CeO₂/NF) via a novel controlled phosphating strategy. The NiP₃@CeO₂/NF catalysts display a fairly small overpotential of 200 mV to achieve a current density of 25 mA cm⁻² for the oxygen evolution reaction (OER) under alkaline conditions, 110 mV smaller than that of NiO@CeO₂/NF. It is noteworthy that the improved electrocatalytic performance of NiP₃@CeO₂/NF can be attributed to rapid electron transfer and the synergistic catalytic effect of the hybrid material. Density functional theory results demonstrate that NiP₃ shows a stronger water adsorption energy than CeO₂. The novel strategy of controlled phosphating to construct transition metal phosphide/oxide interfaces provides new ideas and methods for the development of efficient and practical water splitting catalysts.