Synergistic Mo–Ce dual-active sites for high-yield H₂O₂ electrosynthesis via electrochemical oxygen reduction

Electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (H₂O₂) synthesis offers a sustainable alternative to the anthraquinone process, yet suffers from inherent activity–selectivity tradeoffs. Herein, this work addresses this challenge through the incorporation of Mo into CeO₂ (Mo-CeO₂) featuring oxygen vacancy-mediated Mo–Ce dual-active sites. Mo incorporation into CeO₂ lattice through hydrothermal defect engineering simultaneously elevates oxygen vacancy concentration and induces localized electron redistribution, creating synergistic sites where Mo atoms facilitate proton donation via spontaneous water dissociation while adjacent Ce centers optimize O₂ adsorption configurations to enhance the intrinsic activity of H₂O₂ generation. In-situ characterization and density functional theory calculations reveal that the unique hollow adsorption geometry stabilizes *OOH intermediates and decouples conventional scaling relationships between O₂ adsorption and intermediate binding. This atomic-level cooperativity enables an unprecedented H₂O₂ selectivity of 93%, H₂O₂ yield of 8.2 mol·g_cat⁻¹·h⁻¹ at 100 mA·cm⁻², and exceptional stability. The study establishes an efficient design principle for transition metal oxide catalysts in multi-electron transformations, demonstrating how dual-site engineering can simultaneously enhance intermediate stabilization and reaction kinetics for sustainable electrosynthesis applications.