Dynamic Co(µ-O)₂Ru Moiety Endowed Efficiently Catalytic Hydrogen Evolution

A large number of highly active Ru-based electrocatalysts have been reported for the hydrogen evolution reaction (HER). The utilization of synergistic effects for promoting HER performance remains inadequate, especially for corresponding potential-driven reactive sites at the atomic level. Herein, a Co-substituted Ru-Ru₂P structure is employed as a model system to reveal the synergistic effect on Ru-based electrocatalysts and to realize the potential-driven reactive sites during the HER. Optimized Ru-Ru₂P @ Co_0.6 exhibits a superior catalytic performance in alkaline electrolytes, achieving a low overpotential of 9 mV at a current density of 10 mA cm^–2. To precisely describe the geometrical nature of surface moiety of Co(µ-O)₂Ru, an indicator (β) is established to quantify the strain of Co(µ-O)₂Ru moieties through calculating the L-Co-L (L = P or O) angles through employing in situ X-ray absorption spectroscopy. Both bond strain and corresponding metal-metal distance of Co-Ru in Co(µ-O)₂Ru moiety can significantly affect the structural tolerance and facilitate the coupling of adsorbed hydrogen atoms during HER. It is believed that the perspective raised in the present work will provide a new avenue to the design of highly active HER catalysts at the atomic scale.