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

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/W₂C heterostructure is successfully constructed for effective hydrogen production. Experimental and theoretical results reveal that the Ru nanocluster can effectively stabilize W₂C and thus promote the formation of phase-pure W₂C in the Ru/W₂C heterostructure. In addition, it is revealed that H₂O dissociation proceeded on W₂C, and the formed H intermediates are subsequently migrated to adjacent interfacial Ru sites for H─H coupling and H₂ 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/W₂C 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. © 2024 Wiley-VCH GmbH.