In situ formation of highly exposed NiPS3 nanosheets on nickel foam as an efficient 3D electrocatalyst for overall water splitting

Abstract

The search for cost-efficient and earth-abundant electrocatalysts for the hydrogen evolution reaction/oxygen evolution reaction has received considerable attention. The in situ growth of vertical two-dimensional (2D) nickel phosphorus trisulfide (NiPS₃) nanosheets on nickel foam (NiPS₃/Ni) by one-step chemical vapor transport treatment of nickel foam using red phosphorus and sulfur powder is presented. Benefitting from the unique three-dimensional (3D) structure with a large exposed active surface area from vertically aligned nanosheets and facilitated electron transport along 2D nanosheets anchored on conductive nickel foam, the NiPS₃/Ni electrode requires low overpotentials of 74 mV at 10 mA cm⁻² towards the hydrogen evolution reaction (HER) and 283 mV at 20 mA cm⁻² towards the oxygen evolution reaction (OER) in alkaline solution. Remarkably, the constructed two-electrode alkaline water electrolyzer using NiPS₃/Ni as both anode and cathode catalysts only requires a voltage of 1.60 V to reach a current density of 10 mA cm⁻². The low cost, facile fabrication process, and desirable catalytic performance make the self-supported NiPS₃/Ni electrode a promising electrocatalyst for practical water electrolysis.