Vermicular Ni3S2–Ni(OH)2 heterostructure supported on nickel foam as efficient electrocatalyst for hydrogen evolution reaction in alkaline solution

Abstract Alkaline solution is considered to be more suitable for industrial application of hydrogen production by water electrolysis. However, most of the low-cost electrocatalyts such as Ni3S2 has poor ability to dissociate HO–H, resulting in unsatisfied hydrogen evolution performance in alkaline media. In this paper, a novel vermicular structure of Ni3S2–Ni(OH)2 hybrid have been successfully prepared on nickel foam substrate (v-Ni3S2–Ni(OH)2/NF) through a facile two-step containing hydrothermal and electrodeposition processes. The heterostructure consists of rod-like Ni3S2 and Ni(OH)2 nanosheets, in which Ni(OH)2 is coated on the surface of Ni3S2. This structure not only constructs a fast electron transfer channel but also possesses rich heterointerface, thus accelerating the Volmer step and allowing more active sites of Ni3S2 to functioning well. As a result, v-Ni3S2–Ni(OH)2/NF exhibited excellent electrocatalytic activity toward HER in 1.0 M KOH solution. It only needs 78 mV and 137 mV to drive current density of 10 mA cm−2 and 100 mA cm−2. Moreover, the catalytic stability of this electrocatalyst in alkaline solution is also satisfactory.