Stabilizing Ru Atomic Clusters and Activating Interfacial Water Structure via Bridged p ‐Block In‐N 3 O 1 Single Sites for High‐Performance Alkaline Fuel Cells

ABSTRACT Ru atomic clusters (AC) are promising cost‐effective platinum‐group‐metal anode catalysts for the alkaline hydrogen oxidation reaction (HOR) in anion‐exchange‐membrane fuel cells (AEMFCs), yet their practical application remains limited by insufficient structural robustness and sluggish proton transport across the electrolyte/electrode interface. Herein, we report a design concept that leverages p ‐block indium single atoms with In‐N 3 O 1 coordination as electronic bridges to stabilize Ru AC and reconstruct a proton‐conductive interfacial hydrogen‐bond network for efficient and durable HOR catalysis in practical AEMFCs. We find that the bridged In‐N 3 O 1 sites establish strong covalent Ru‐In anchoring interactions through pronounced d‐p orbital hybridization, stabilizing Ru AC against coalescence and detachment for markedly improved operational durability. Meanwhile, electronic coupling between Ru AC and bridged In‐N 3 O 1 sites tunes surface oxophilicity of Ru to promote higher coverage of hydroxyl adsorbate species and drive dynamic reorientation of interfacial water from cation‐bound states toward free water in the gap region, thereby reinforcing hydrogen‐bond connectivity and enabling more efficient interfacial proton transport. The resulting Ru AC/In 1 @CNO delivers a mass activity of 7.17 A mg Ru −1 , surpassing Pt/C by 9.0‐fold. Particularly, Ru AC/In 1 @CNO‐based AEMFCs achieve a high peak power density of 1.33 W cm −2 and maintain stable operation for over 50 h at 500 mA cm −2 .