Electronic structure engineering of CoS catalysts by rhenium modification for efficient alkaline hydrogen evolution

Fabricating a durable electrocatalyst with performance comparable to noble metals for the alkaline hydrogen evolution reaction (HER) remains a significant challenge. In this work, we introduce a highly efficient and robust electrocatalyst by incorporating rhenium (Re) atoms into CoS nanoflakes (Re-CoS) for alkaline HER. The incorporation of Re atoms into the CoS lattice enhances the hybridization of Co 3d and S 2p orbitals, resulting in an optimized electronic structure that accelerates water dissociation on Co sites and optimizes hydrogen adsorption–desorption on S sites, thereby boosting the HER rate. The optimal Re-CoS catalyst demonstrates a low overpotential of 72 mV at 10 mA cm⁻² in 1 M KOH, along with excellent long-term stability, maintaining its catalytic activity over 200 h without significant degradation. These results suggest that the incorporation of Re atoms into CoS effectively couples the water dissociation and hydrogen ad-desorption steps of alkaline HER, offering a promising strategy for the development of noble metal-like electrocatalysts.