▎ 摘　　要

The alkaline hydrogen evolution reaction (HER) is a promising method for the large-scale production of high-purity hydrogen. Currently, major challenges in the fabrication of highly efficient and cost-effective HER electrocatalysts for alkaline conditions are related to the considerably sluggish water dissociation and the massive use of precious metals. Herein, we propose a facile strategy to encapsulate Ru-substituted Co nanoparticles within few-layer N-doped graphene (2-5 layers), exhibiting robust and highly active performance in water electrolysis. The optimized catalyst with a tiny Ru substitution (similar to 5.55 wt%) displays a low overpotential of -34 mV at 10 mA/cm(2), the high mass activity of 10.99 A/mg((Ru)) at -50 mV, and excellent durability in 1 M KOH over 16 h, even better than commercial Pt/C. Experimental and computational studies (density functional theory) demonstrate that the tiny Ru substitution greatly accelerates the water capture and dissociation rates, and improves the electrochemical hydrogen evolution in basic electrolytes. This work delivers in-depth insights into the relationship between the apparent alkaline-HER activity and the intermediate adsorbed state and provides a promising strategy for designing and synthesizing efficient electrocatalysts that enhance the alkaline-HER activity.