Transition Metal-Doped Mo-Vacancy Defects at MoS₂ Basal Plane for Enhanced Hydrogen Evolution Catalysis

In this work, we explored transition metal-doped Mo-vacancy defects in MoS₂ for hydrogen evolution catalysis using DFT calculations. We found that transition metals (V, Cr, Mn, Fe, Co, Ni) preferentially incorporate at Mo-vacancy sites, creating electronically modified regions with enhanced catalytic properties. Early transition metals (V, Cr, Mn) establish near-optimal hydrogen binding energies (0.18–0.23 eV) at adjacent sulfur sites, dramatically improving the otherwise inert basal plane. Electronic structure analysis revealed a direct correlation between Bader charge distribution and hydrogen binding strength, providing mechanistic insights. Additionally, our findings suggest potential bifunctional catalysis in alkaline media, where neighboring sites perform complementary roles in water dissociation and hydrogen adsorption. These results offer new strategies for designing efficient MoS₂-based electrocatalysts through strategic defect engineering.