NiFeP nanosheets on N-doped carbon sponge as a hierarchically structured bifunctional electrocatalyst for efficient overall water splitting

The advancement of high-performance and low-cost bifunctional electrocatalysts, for the hydrogen and oxygen evolution reaction (HER and OER), is significant to realize the commercialization of electrocatalytic overall water splitting. Herein, two-dimensional (2D) holey NiFeP nanoarrays are vertically grown on a threedimensional (3D) porous nitrogen-doped carbon sponge (N-CS) to form a hierarchically self-supported electrocatalyst (named NiFeP@N-CS) for efficient water splitting. Benefiting from the bimetal synergy effect and the hierarchical structure, the obtained bifunctional electrocatalyst NiFeP@N-CS exhibits high electrocatalytic performance for HER and OER (186 mV and 216 mV at 10 mA cm(-2)) in 1.0 M KOH. As a result, the water electrolyzer assembled by NiFeP@N-CS electrocatalyst as both anode and cathode only requires 1.63 V at the same current density and maintains outstanding durability up to 24 h. The present work extends the application of electrocatalysts with the hierarchical structure in the field of electrochemical overall water splitting.