Construction of NiP/WS/CoWO@C multi-heterojunction electrocatalysis derived from heterometallic clusters for superior overall water splitting.

The reasonable design of an economical and robust bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is both essential but challenging. Herein, we synthesized a multi-interfacial NiP/WS/CoWO@C hybrid electrocatalyst devived from the heterometallic clusters [Co(TC4A)(WO)Cl][HPWO], in which NiP was incorporated into WS/CoWO@C nanosheets via interfacial interactions by in situ phosphorization processes. Theoretical calculations revealed that moderate electron transfer from CoWO and NiP to WS induced by the multi-heterojunction significantly regulate the binding energies of the reactive intermediates, thus enhacing its intrinsic activity. Under alkaline medium, the overpotential of the optimized NiP/WS/CoWO@C electrocatalyst for OER and HER is only 206 mV and 90 mV at 10 mA cm, respectively, with extraordinary stability more than 100 h, and the potential of overall water splitting is only 1.46 V. This work motivates further research and presents a reliable design route for other heterojunction engineered cost-effective bifuctional electrocatalysts.