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

The MoS2/NiS-Ni3S2 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 MoS2/NiS-Ni3S2 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, MoS2/NiS-Ni3S2 can run stably for 12 h at 200 mA cm(-2) current density without obvious fluctuation, showing excellent durability. Meanwhile, MoS2/NiS-Ni3S2 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 MoS2/NiS-Ni3S2 make it become a powerful competitor for the high activity bifunctional non-noble-metal electrocatalysts. (C) 2019 Elsevier Ltd. All rights reserved.