Water electrolysis offers a zero-carbon route to generate renewable energy conversion systems. Herein, a self-supported nickel phosphosulfide nanosheet (NS) electrocatalyst was fabricated at a low temperature on carbon cloth, which was then subjected to Ar etching to enhance its catalytic activity. Etching resulted in better hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance than other samples, with overpotentials of 103.1 mV (at 10 mA cm-2) and 278.9 mV (at 50 mA cm-2), respectively. The characterization results confirmed that Ar etching created a thin amorphous layer around the NiPS3 NSs, which increased the number of active sites and modulated their electronic structures. These 3D-structured NiPS3 NSs and their subsequent Ar etching process show promise for applications in overall water splitting in alkaline media.
Keywords: Ni-based nanomaterials; hydrogen evolution reaction; oxygen evolution reaction; plasma surface treatment; vacancy defect; water splitting.