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

Abstract

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.

Tailoring iridium–palladium nanoparticles with Ir-rich skin: a highly durable anode electrocatalyst for acidic water electrolysis via a facile microwave-assisted chemical reduction method

“…2 Although both of the these reactions require catalysis to obtain meaningful reaction rates at low overpotentials, the OER, owing to its complex mechanism comprising numerous electron transfer stages with sluggish kinetics, is challenging when compared to HER. 4,5 Despite substantial progress in the design of nonnoble transition metal-based HER/OER electrocatalysts [6][7][8][9][10] that can work in neutral and basic electrolytes, 7,8,[11][12][13] finding efficient and stable HER/OER electrocatalysts that can withstand acidic electrolytes still remains largely unsettled. This issue is appealing because acidic electrolytes have specific advantages over alkaline electrolytes in both HER and OER, allowing better ionic conductivities and avoiding the production of carbonate impurities.…”