Asymmetric electronic polarization in Ni–P–Co for efficient overall water splitting

Abstract

Developing bifunctional electrocatalysts that simultaneously boost hydrogen evolution and oxygen evolution remains challenging owing to the inherent trade-off in adsorption energetics of key intermediates. Herein, a Mo,W-dual-doped NiCoP catalyst supported on nickel foam (Mo,W-NiCoP/NF) was successfully synthesized, achieving exceptional overall water splitting performance. Mo,W-NiCoP/NF only requires 129 mV for the hydrogen evolution reaction (HER) and 126 mV for the oxygen evolution reaction (OER) at 100 mA cm⁻² in alkaline media and delivers 1.79 V at 100 mA cm⁻² for overall water splitting with outstanding durability over 100 h. The key innovation lies in an asymmetric electronic polarization effect induced by the high-electronegativity Mo/W dopants. Specifically, Ni sites become electron-rich to optimize proton adsorption for the HER, while Co sites become electron-deficient to enhance the binding of oxygen-containing intermediates for the OER. This work establishes asymmetric electronic polarization as a powerful and general strategy to break activity trade-offs in bifunctional catalysis.