Nitrogen-Doped NiS/WS₂ Heterostructures on Carbon Cloth: A Synergistic Route to High-Performance Hydrogen Evolution...

Developing efficient and stable hydrogen evolution electrocatalysts from transition metal sulfides is highly significant for promoting the practical application of electrochemical water splitting for hydrogen production. Rational design of catalysts by constructing heterostructures and doping elements may potentially achieve this goal. In this article, a simple hydrothermal method combined with a urea-assisted annealing process was used to successfully fabricate a nitrogen-doped NiS/WS₂ heterostructured composite material with a three-dimensional flower-like morphology (N-NiS/WS₂/CC). This catalyst exhibited excellent hydrogen evolution reaction (HER) electrocatalytic performance in a 1 mol/L KOH electrolyte: At a current density of 10 mA/cm², the overpotential was only 96.1 mV, significantly superior to the single WS₂ control sample. The results of density functional theory (DFT) calculations indicated that the heterojunction formed at the interface of NiS and WS₂ and the introduction of nitrogen atoms jointly regulated the electronic structure of WS₂, not only enhancing the overall conductivity but also effectively reducing the hydrogen adsorption free energy (G_H*), thereby facilitating the adsorption/desorption of H and boosting the HER activity. Moreover, N-NiS/WS₂/CC exhibited excellent stability in the durability test. The proposed method in this study provides a feasible solution for the synthesis of low-cost electrocatalysts.