Hydrogen Spillover-Bridged Interfacial Water Activation of WCx and Hydrogen Recombination of Ru as Dual Active Sites for Accelerating Electrocatalytic Hydrogen Evolution

Tungsten carbide (WC x ) is a promising alternative to platinum catalysts for hydrogen evolution reaction (HER). However, strong tungsten–hydrogen bond hinders hydrogen desorption while favoring H + reduction, thus limiting HER kinetics. Inspired by the phenomenon of hydrogen spillover in heterogeneous catalysis, a ruthenium (Ru) doped-driven activated hydrogen migration from WC x surface to Ru is reported. This approach achieved high activity with an ultralow overpotential of 9.0 mV at 10 mA·cm −2 and superior stability at an industrial-grade current density of 1.0 A·cm −2 @ 1.65 V. In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and operando electrochemical impedance spectra revealed that this exceptional hydrogen production—which surpasses that of previously reported Pt/C catalysts—is attributable to the outstanding ability of WC x to induce water dissociation and hydrogen spillover from WC x to Ru surface. During the HER process, the rigid interfacial water network negatively affected the HER efficiency under alkaline conditions. The WC x sites disrupted this rigid structure, facilitating the contact between activated hydrogen (H * ) and WC x sites. Subsequently, H * migrates to Ru surface, where hydrogen recombination occurs to produce H 2 . This work paves a new avenue for the construction of coupled catalysts at the atomic scale to facilitate HER electrocatalysis.