Atomically Modulating Metal‐Support Interactions by Isolated Co‐N₄ Sites for Efficient Hydrogen Oxidation Catalysis

Abstract Supported metal electrocatalysts with appropriate metal‐support interactions (MSIs) show great potential for heterogeneous catalysis, however, precisely tuning the interactions at an atomic level remains a significant challenge. In this work, single‐atom Co‐N₄ sites are introduced to tailor the interfaces between PtIr alloy clusters and carbonaceous substrates, thereby establishing highly active and stable catalysts toward hydrogen oxidation reaction (HOR) in alkaline electrolytes and realizing atomically MSIs modulation. The experimental and theoretical results unveil that the formation of robust MSIs at the interfaces with the incorporation of Co single atoms is evidenced by the increased coordination number of Pt‐N/C, which effectively optimizes the adsorption behaviors of H_ad on Pt/Ir atoms and also tightly immobilizes PtIr clusters on the supports. The incorporation of isolated Co‐N₄ sites greatly reduces the energy barrier of the rate‐determining Volmer step, thereby accelerating the HOR reaction kinetics in alkaline electrolytes. Consequently, the optimal PtIr‐Co_0.05NC catalysts exhibit exceptional HOR activity with an exchange current density up to 13.1 mA cm⁻² and a kinetics current density of 28.8 mA cm⁻² at 50 mV in 0.1 m KOH. Furthermore, the PtIr‐Co_0.05NC electrocatalyst delivers negligible activity degradation due to the confinement effect of Co‐functionalized carbon supports on PtIr clusters.