Self-supported 3D porous N-Doped nickel selenide electrode for hydrogen evolution reaction over a wide range of pH

Abstract

Transition metal dichalcogenides (TMD) are regarded as suitable substitutes for precious Pt as the hydrogen evolution catalysts due to their low cost and unique electronic structure. However, the bulk crystals of these materials are good conductors but show poor catalytic performance, whereas their nanostructures exhibit better activity but lower conductivity. In this study, a self-supported three-dimensional (3D) porous nitrogen-doped nickel selenide (NNiSe2) electrode is constructed and its HER activities over a wide range of pH are evaluated. Especially, only an overpotential of 86 mV is needed to afford the current density of 10 mA cm−2 in an alkaline medium (1.0 M KOH, pH = 14). Density functional theory (DFT) calculations show that NNiSe2 has lower Gibbs free-energy of H (ΔGH*) and water adsorption energy (ΔGH2O*) compared to pristine NiSe2, revealing that the catalyst-H* and catalyst-H2O state are easily to occur on the surface of NNiSe2 and finally enhance the HER activity. The as obtained NNiSe2 can be a potential non-noble-metal catalyst for practical hydrogen evolution reaction application.