Synthesis of 3D flower-like nickel-molybdenum-sulfur microspheres as efficient and stable electrocatalyst for hydrogen and oxygen evolution reactions

The MoS 2 /NiS–Ni 3 S 2 core-shell structure with flower-like microspheres morphology is a product of reasonable construction on nickel foam. The synergistic effect of heterostructure and abundant active sites make the catalyst exhibits excellent performance in alkaline solution, especially at high current. Specifically, at 200 mA cm −2 current density, the MoS 2 /NiS–Ni 3 S 2 composite exhibits small overpotential of 181 mV and Tafel slope of 70.0 mV dec −1 for hydrogen evolution reaction, and low overpotential of 460 mV and Tafel slope of 30.3 mV dec −1 for oxygen evolution reaction. Moreover, MoS 2 /NiS–Ni 3 S 2 can run stably for 12 h at 200 mA cm −2 current density without obvious fluctuation, showing excellent durability. Meanwhile, MoS 2 /NiS–Ni 3 S 2 as an electrolyzer achieves a current density of 10 mA cm −2 at 1.49 V, without decay after a durability test of 12 h. These superior properties of the MoS 2 /NiS–Ni 3 S 2 make it become a powerful competitor for the high activity bifunctional non-noble-metal electrocatalysts .