WS2/NiSx heterojunction nanosheet clusters: A highly efficient electrocatalyst for hydrogen evolution reaction

The development of highly active and stable electrocatalysts is essential to solve energy and environmental problems and realize sustainable social and economic development. Herein, we synthesized a bimetallic sulfide material by a kinetically controlled low-temperature solid-phase reaction. The bimetallic sulfide improves the conductivity of the electrocatalysts by optimized electronic structure, and the coupling effect at the heterogeneous interface of WS2 and NiSx increases the charge density on the S site at W–S–Ni, making it easier for the electrocatalysts to trap the active material in solution. In addition, nanosheet clusters expose abundant catalytic sites, which together improve hydrogen evolution reaction (HER) for catalytic activity. Optimized WS2/NiSx composite show near-precious metal catalyst activity with an overpotential at 10 mA cm−2 of only 72 mV in alkaline media, which exhibits excellent catalytic stability and outperforms most non-precious metal electrocatalysts.