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

Tungsten carbide (WCx) 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 WCx 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 WCx to induce water dissociation and hydrogen spillover from WCx to Ru surface. During the HER process, the rigid interfacial water network negatively affected the HER efficiency under alkaline conditions. The WCx sites disrupted this rigid structure, facilitating the contact between activated hydrogen (H*) and WCx 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. Inspired by the phenomenon of hydrogen spillover in heterogeneous catalysis, the well‐designed Ru/WCx not only improved the H2O dissociation process by facilitating contact between activated hydrogen and WCx sites, but also increased hydrogen production via hydrogen spillover on Ru sites. The optimal Ru/WCx demonstrates ultra‐high HER performance with an overpotential of only 9 mV at 10 mA·cm−2.