Atomic‐Scale Configuration Enables Fast Hydrogen Migration for Electrocatalysis of Acidic Hydrogen Evolution

Abstract The efficiency of hydrogen evolution reaction (HER) electrocatalysts under acidic conditions is largely determined by the equilibrium of hydrogen adsorption/desorption on the catalyst surface. A promising strategy for enhancing the performance of multimetal‐supported HER electrocatalysts is the utilization of hydrogen spillover. However, current heterostructured catalysts often present challenges such as high interfacial transport barriers, extended reaction paths, and intricate synthesis processes. Addressing these limitations, a novel orthorhombic SrHf 1− x Ru x O 3− δ perovskite oxide is proposed as an exemplary model for an atomic‐level configuration design strategy. This material exhibits a unique synergistic effect of multiple atomic‐level catalytic sites between Hf/Ru pairs, overcoming the aforementioned challenges. This study presents a new cooperative mechanism for HER, consisting of three steps: proton adsorption on the Hf site, hydrogen migration via a strong O‐bridge site, and H 2 detachment from the Ru active site. The high conductivity and unusual charge redistribution within the Hf‐O‐Ru structure further enhance the specific acidic HER activity of SrHf 1− x Ru x O 3− δ . This research paves the way for designing high‐performance HER catalysts for acidic media, leveraging hydrogen spillover and atomic‐scale configurations. The findings have significant implications for the development of efficient, cost‐effective, and environmentally friendly hydrogen production technologies.