Hydrogen Spillover‐Bridged Interfacial Water Activation of WC _x 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 H₂. This work paves a new avenue for the construction of coupled catalysts at the atomic scale to facilitate HER electrocatalysis.