Polysulfide-Induced Synthesis of Hierarchical Ni₃S₂/NiCo₂S₄ Nanorods Supported on Nickel Foam for Boosted Oxygen Evolution Catalysis

Crystal structures and chemical states can be reconstructed by inducing the positioning growth of metal sulfide, which is an efficient strategy to enhance the oxygen evolution activity of an anode. In this paper, polysulfide (Poly(S-r-DIB))-induced S-doped hierarchical heterostructures Ni 3 S 2 /NiCo 2 S 4 were successfully grown on nickel foam (Ni 3 S 2 /NiCo 2 S 4 /NF) by an in situ solvothermal sulfuration reaction using polysulfide as the sulfur source. The unique hierarchical heterostructure and strong electron interaction in Ni 3 S 2 @NiCo 2 S 4 /NF increased the catalytic activity area and provided more mass transfer channels for electron transfer to facilitate water splitting. As-prepared Ni 3 S 2 /NiCo 2 S 4 /NF exhibits excellent electrocatalytic activity for oxygen evolution reaction (OER) with an ultralow overpotential of 330 mV to reach 100 mA cm –2 and a small Tafel slope of 67.6 mV dec –1, which is superior to most reported nickel-based sulfide electrocatalysts. This study provides not only a new method for the design of hierarchical nanomaterials but also an efficient strategy to design efficient OER electrocatalysts by an in situ polysulfide confinement method.