Recent progress of photo-electrochemical hydrogen peroxide production and its cascade reaction

Abstract

Hydrogen peroxide (H₂O₂), as a green and versatile oxidant, holds significant promise across environmental and energy-related applications. However, its industrial production via the conventional anthraquinone process is plagued by issues including raw material hazards, high energy consumption, complex separation processes, and safety concerns in storage and transportation. In response, photo-electrochemical production has emerged as a sustainable alternative for on-site H₂O₂ synthesis via two-electron pathways, namely the oxygen reduction reaction (ORR) and water oxidation reaction (WOR). This review systematically summarizes recent progress in photo-electrochemical H₂O₂ production, focusing on fundamental mechanisms, catalyst design strategies, and system-level innovations. The working principles of photo-electrochemical systems are amply introduced, emphasizing charge separation and surface reaction dynamics. Subsequently, the thermodynamic and kinetic characteristics of ORR and WOR pathways are analyzed, with an emphasis on selectivity regulation between two-electron and four-electron routes. Advances in photo-electrochemical materials are comprehensively reviewed. Key performance indicators such as faradaic efficiency (FE), H₂O₂ yield, and stability are critically evaluated. Furthermore, emerging applications integrating H₂O₂ production with environmental remediation (e.g., pollutant degradation, disinfection) and energy conversion systems (e.g., H₂O₂ fuel cells) are discussed, along with reactor design and scale-up strategies. Finally, current challenges and future directions are outlined, including stability enhancement, selectivity control, and the integration of renewable energy sources. This review aims to provide a comprehensive reference for advancing green and decentralized H₂O₂ production through photo-electrochemical technologies.