Dual‐Site Engineering Promotes Oxygen Evolution Reaction of Acidic Water Electrolysis over RuO 2

Abstract Hydrogen energy, as a clean energy carrier with zero carbon emissions, relies on breakthroughs in proton exchange membrane water electrolysis (PEMWE) technology for its efficient production. Although ruthenium dioxide (RuO 2 ) exhibits excellent electrocatalytic performance, the dissolution of lattice oxygen in acidic media under high anodic potentials and the excessive oxidation of ruthenium species lead to a rapid decline in catalytic performance. This significantly hinders its practical application. In this study, the design of thulium‐doped RuO 2 (Tm‐RuO 2 ) catalysts via a mild hydrolysis approach is demonstrated, which necessitates merely an overpotential of 201 mV in 0.5 m H 2 SO 4 to sustain an oxygen evolution reaction (OER) current density of 10 mA cm −2 . Moreover, the catalyst exhibits stable operation for 200 h at 10 mA cm −2 without any discernible activity decay. Theoretical investigations have revealed that Tm doping, by optimizing the electronic structure of Ru─O bonds and modulating the adsorption strength of intermediates, facilitates a shift in the reaction pathway from the lattice oxygen mechanism (LOM) to the adsorption evolution mechanism (AEM). This synergistic effect enhances both catalytic activity and structural stability. These findings offer a viable strategy for future investigations into the stability of ruthenium‐based oxide catalysts in acidic environments.