Construction of Ni2P/WS2/CoWO4@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 multiinterfacial Ni2P/WS2/CoWO4@C hybrid electrocatalyst devived from the heterometallic clusters [Co-24(TC(4)A)(6)(WO4)(8)Cl-6][HPW12O40], in which Ni2P was incorporated into WS2/CoWO4@C nanosheets via interfacial interactions by in situ phosphorization processes. Theoretical calculations revealed that moderate electron transfer from CoWO4 and Ni2P to WS2 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 Ni2P/WS2/CoWO4@C electrocatalyst for OER and HER is only 206 mV and 90 mV at 10 mA cm(-2), 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.