Engineering Doping and Vacancy in a C₃N₄Electrocatalyst with Ni₄Mo Cocatalyst for Efficient Alkaline Hydrogen Evolution

To meet the growing demand for sustainable hydrogen production, robust and cost-effective electrocatalysts are essential, especially under alkaline conditions. Herein, we report a phosphorus-doped carbon nitride (P–C₃N₄) electrocatalyst exhibiting remarkable hydrogen evolution reaction (HER) performance in an alkaline electrolyte. Phosphorus doping was found to promote electronic conductivity and create Lewis acidic active sites, facilitating water dissociation and hydrogen adsorption. Electrochemical measurements revealed a significant reduction in overpotential and Tafel slope upon optimal P-doping (2.0 at%). Further introduction of nitrogen vacancies (NV) and coloading with Ni₄Mo bimetallic alloy synergistically enhanced the catalytic activity, delivering an overpotential (η₁₀) as low as 93 mV at −10 mA·cm^–2 and a Tafel slope of 88 mV·dec^–1, without reliance on noble metals. These results underscore the promise of defect-engineered C₃N₄ systems as viable catalysts for green hydrogen generation.