Lattice‐Matched Ru/W₂C Heterointerfaces with Reversible Hydrogen Spillover for Efficient Alkaline Hydrogen Evolution

Abstract The effect of lattice‐matched heterointerfaces on the hydrogen reverse spillover process for accelerating alkaline hydrogen evolution reaction (HER) kinetics has not yet been reported. Herein, a lattice‐matched Ru/W 2 C heterostructure is successfully constructed for effective hydrogen production. Experimental and theoretical results reveal that the Ru nanocluster can effectively stabilize W 2 C and thus promote the formation of phase‐pure W 2 C in the Ru/W 2 C heterostructure. In addition, it is revealed that H 2 O dissociation proceeded on W 2 C, and the formed H intermediates are subsequently migrated to adjacent interfacial Ru sites for H─H coupling and H 2 release. This is enabled via a reversible hydrogen spillover mechanism promoted by the lattice‐matched heterointerfaces that can weaken interfacial proton adsorption. As expected, the Ru/W 2 C heterogeneous electrocatalyst exhibited a superior HER performance with a low overpotential of 17 mV at 10 mA cm −2 , a high mass current density (6.44 A mg Ru −1 ), and a low turnover frequency (TOF) value (2.8 s −1 ) at the overpotential of 100 mV, far overwhelming the benchmark Ru/C and Pt/C. The study may offer a new perspective for the design of highly active electrocatalysts for alkaline HER.