Beyond Electronic Interaction: Ru Sub‐Nanoparticles Reconfiguring Interfacial Water on Ru–Co Diatomic Sites for Accelerated Oxygen Reduction

ABSTRACT Synergy between metallic nanoparticles and single‐atom sites offers considerable potential for developing advanced electrocatalysts. However, the synergistic mechanism in such complex architectures under operating conditions remains elusive. Herein, a two‐step approach involving selective etching and co‐confined adsorption was developed to precisely construct CoRu/Ru NPs catalyst, featuring Ru–Co diatomic sites coupled with Ru sub‐nanoparticles, which demonstrates excellent oxygen reduction reaction (ORR) performance with a half‐wave potential of 0.91 V and a peak power density of 369 mW cm −2 in zinc‐air batteries, along with outstanding cycling stability over 1350 h. Beyond modulating the electronic structure to weaken OH* adsorption on Ru–Co diatomic sites, the Ru sub‐nanoparticles also induce an alternative thermodynamic pathway for enhanced ORR kinetics, in which interfacial water dissociate on oxyphilic Ru sub‐nanoparticles and facilely supply protons to oxygen‐containing intermediates on neighboring Ru–Co diatomic sites. This work not only advances the construction of synergistic active sites but also opens a new paradigm for designing advanced electrocatalysts by harnessing the interfacial environment beyond electronic structure modulation.