Hydrogen Spillover Enabled by Edge Dislocations for Efficient Hydrogen Evolution

Abstract Designing an efficient alkaline hydrogen evolution reaction (HER) catalyst requires enhanced hydrogen adsorption to facilitate water dissociation while noting that this would be detrimental to H₂ desorption. Although hydrogen spillover‐assisted HER has been emerging as a promising strategy due to separated active sites for water dissociation and hydrogen formation enabled by heterogeneous catalysts, interfacial charge accumulation, and strong interfacial proton adsorption would hinder proton transfer due to a high energy barrier. Herein, a novel strategy to realize hydrogen spillover‐assisted HER enabled by edge dislocations of Mo₂C catalyst is presented. The coupled tensile‐compressive strain regions induced by edge dislocations serve as nano‐reactors for HER. The Volmer process is greatly enhanced by strong water adsorption and efficient ^*H₂O dissociation in the tensile regions, meantime the generated ^*H rapidly transfers to the compressive regions for easy hydrogen molecule release. As a result, the edge dislocation‐rich catalyst achieves a low overpotential of only 61 and 179 mV at 10 and 300 mA cm⁻², showcasing a new way to apply hydrogen spillover in single‐phase catalysts and offering potential for developing cost‐effective and efficient HER catalysts.