Intensifying the Supported Ruthenium Metallic Bond to Boost the Interfacial Hydrogen Spillover Toward pH-Universal Hydrogen Evolution Catalysis

The effectuation of pH-universal electrocatalysis is highly attractive but still challenging for the hydrogen evolution reaction (HER). It appeals for not only the facilitated electron transport but also the kinetical proton mass transfer. In this study, a via-hole Ru/MoO₂ confined heterostructure is profiled as a metal-support platform for the electron/mass transfer-boosted pH-universal HER studies. It is indicated that the as-formed Ru─O─Mo bridge can modulate the electronic transport at the interface, and the proton adsorption and transfer are kinetically derived by the intensified metallic Ru─Ru bond. Resultantly, the Ru/MoO₂ heterostructure stably attains the Pt-beyond HER activity with an ultralow overpotential of 9.2 mV at 10 mA cm⁻² in 1 m KOH, and also achieves the competitive HER activity and stability in the acidic/neutral electrolytes. Both the experimental and computational results reveal the accelerated HER kinetics is attributable to the intensive mass transfer through the interfacial Ru→MoO₂ hydrogen spillover effect. This work opens up the opportunities to rationalize the advanced metal-support HER electrocatalysts through the interfacial hydrogen spillover effect and metallic bond engineering.