Electronic structure engineering via Nb doping in nanostepped WSe₂ for platinum-competitive hydrogen evolution

Advancing high-performance electrocatalysts for the hydrogen evolution reaction (HER) is a prerequisite for eco-friendly and industrial-scale hydrogen generation from water. While conventional catalysts still utilize costly platinum-based materials, the development of high-performance, non-precious metal alternatives is urgently required. We report a monolithic Nb-doped WSe₂ (Nb-WSe₂) catalyst with a unique nano-step-like morphology. The catalyst exhibits outstanding electrocatalytic efficiency and stability, demonstrated by low overpotentials of merely 27 mV at 10 mA/cm² and 158 mV at a high current density of 1200 mA/cm², coupled with a small Tafel slope of 33.5 mV/dec. The remarkable catalytic efficiency of Nb-WSe₂ can be ascribed to its unique electron transfer capability as a monolithic catalyst, the abundant edges provided by the nanoscale step morphology, and the enhanced active sites resulting from Nb doping. Density functional theory calculations indicate that Nb doping enhances the active sites and optimizes hydrogen adsorption. This work presents Nb-WSe₂ as a highly promising and cost-effective catalyst for hydrogen production, setting the stage for advanced and sustainable energy applications.