Bidirectional Electron Relay at TiN‐TiO₂ Interfaces Enables Oxidation‐Resistant Ru for High‐Potential Hydrogen Oxidation Catalysis

Ruthenium-based catalysts are pivotal as cost-effective alternatives to Pt for alkaline hydrogen oxidation reaction (HOR). However, they typically face irreversible deactivation above 0.2 V vs. RHE due to synergistic Ru oxidation/OH_ad over-adsorption. We propose a Taichi-inspired TiN-TiO₂ heterophase-segregated electron-relay mechanism that dynamically balances bidirectional electron flow (Ru→TiN electron donation and TiO₂→Ru electron replenishment), achieving complete activity retention (100%) even under 1.1 V operation. This potential-adaptive regulation can significantly inhibit electron redistribution and band compression under the high potential induced electric field, and effectively alleviate the d-band upshift and OH adsorption energy surge. Spatially decoupled Ti(TiN)-Ru bridge sites simultaneously adsorb OH_ad (E_ads = -1.40 eV) and decouple H_ad/OH_ad adsorption domains, eliminating competitive binding. This configuration delivers triple synergies: 1) geometric isolation of reactive intermediates adsorption, 2) potential-responsive Ru⁰ stabilization, and 3) accelerated Volmer kinetics via interfacial hydroxyl migration. The Ru/TiN-TiO₂ catalyst achieves 100% activity retention at 1.1 V vs. RHE (vs. >60% loss for Ru/TiN) with 73.23% metallic Ru⁰ preserved after 10 h operation. This work resolves the intrinsic activity-stability trade-off in Ru HOR catalysts and establishes dynamic charge-relay interfaces as a universal design paradigm for oxidation-prone electrocatalysts.