Mo, Co co-doped NiS bulks supported on Ni foam as an efficient electrocatalyst for overall water splitting in alkaline media
In this work, Mo, Co co-doped NiS bulks grown on Ni foam (Mo,Co-NiS/NF) was synthesized as a bi-functional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) using a simple method. The existence of ZIF-67 and Mo could make sure the evenly distribution of Co and Mo element and the formation of N doped carbon layer in Mo,Co-NiS/NF. Mo, Co co-doping and NF-supporting greatly improved the electrocatalytic performance of NiS bulks because metal element doping could improve the intrinsic activity and electrical conductivity, meanwhile, Ni foam could act as a substrate to avoid aggregation and provide nickel source to form bimetallic sulfide. The product Mo,Co-NiS/NF-400 showed outstanding electrchemical property with ultralow overpotential (92 mV vs. RHE) for HER and ultralow overpotential (81 mV vs. RHE) for OER to achieve 10 mA cm-2 and the ultralow cell voltage (1.36 V) to achieve 20 mA cm-2 for overall water splitting. This work provided an available method to promote the electrocatalytic activity of traditional monometallic sulfides for overall water splitting.