Metal-Based Oxygen Reduction Electrocatalysts for Efficient Hydrogen Peroxide Production

Hydrogen peroxide (H₂O₂) is a high-value chemical widely used in electronics, textiles, paper bleaching, medical disinfection, and wastewater treatment. Traditional production methods, such as the anthraquinone oxidation process and direct synthesis, require high energy consumption, and involve risks from toxic substances and explosions. Researchers are now exploring photochemical, electrochemical, and photoelectrochemical synthesis methods to reduce energy use and pollution. This review focuses on the 2-electron oxygen reduction reaction (2e⁻ ORR) for the electrochemical synthesis of H₂O_2, and discusses how catalyst active sites influence O₂ adsorption. Strategies to enhance H₂O₂ selectivity by regulating these sites are presented. Catalysts require strong O₂ adsorption to initiate reactions and weak *OOH adsorption to promote H₂O₂ formation. The review also covers advances in single-atom catalysts (SACs), multi-metal-based catalysts, and highlights non-noble metal oxides, especially perovskite oxides, for their versatile structures and potential in 2e⁻ ORR. The potential of localized surface plasmon resonance (LSPR) effects to enhance catalyst performance is also discussed. In conclusion, emphasis is placed on optimizing catalyst structures through theoretical and experimental methods to achieve efficient and selective H₂O₂ production, aiming for sustainable and commercial applications.