Mn-Oxygen Compounds Coordinated Ruthenium Sites with Deprotonated and Low Oxophilic Microenvironments for Membrane Electrolyzer-based H 2 -Production.

Among the platinum-group metals, ruthenium (Ru), with a low water dissociation energy, has been considered a promising alternative to substitute Pt for catalyzing hydrogen evolution reaction (HER). However, optimizing the adsorption/desorption energies of H* and OH* intermediates on Ru catalytic sites is extremely desirable but remains challenging. Inspired by the natural catalytic characteristics of Mn-oxygen complex, we report to design Mn-oxygen compounds coordinated Ru sites (MOC-Ru) with deprotonated and low oxophilic microenvironments for modulating the adsorption/desorption of H* and OH* to promote HER kinetics. Benefiting from the unique advantages of MOC structures, including weakened H-OH bond at interface, electron donation ability, and deprotonation capability, the MOC-Ru exhibits extremely low overpotential and ultralong stability in both acidic and alkaline electrolytes. Experimental observations and theoretical calculations elucidate that the MOC can accelerate water dissociation kinetics and promote OH* desorption in alkaline conditions, and trigger the long-range H* spillover for H 2 -release in acid conditions. The outstanding activity and stability of membrane electrolyzer display that the MOC-Ru catalyst holds great potential as cathode for H 2 -production. This study provides essential insights into the crucial roles of deprotonated and low oxophilic microenvironments in HER catalysis and offers new pathway to create efficient water-splitting cathode. This article is protected by copyright. All rights reserved.