Interface Engineering of Ni2P/Ni4W Heterostructures with Electron Pump for Efficient Overall Water Splitting

Local charge redistribution plays a key role in accelerating the kinetics of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) for efficient overall water splitting. Herein, the Ni2P/Ni4W/NF heterostructure with a fast electron pump and numerous boundaries is constructed by interface engineering. The Ni2P–Ni4W/NF catalyst required overpotentials of only 237 mV and 327 mV to achieve a current density of 200 mA cm–2 for HER and OER in alkaline media, which can be ascribed to the optimized electron distribution and defect-rich boundaries. Density functional theory (DFT) calculations reveal that the difference of work function supports a sustainable electron flow from Ni4W to Ni2P, which can facilitate the kinetics of OER and HER. Moreover, the catalyst exhibited excellent long-term stability for 100 h at an industrial-scale current density of 500 mA cm–2. This work provides a feasible engineering strategy for designing high-performance heterojunction electrocatalysts.