Challenges and Prospects of Catalyst Design and Environmental Applications for On-Site Hydrogen Peroxide Production via Diverse (Photo)Electrochemical Reaction Pathways

Hydrogen peroxide (H₂O₂) is an environmentally friendly and efficient oxidant with diverse applications in the chemical industry, medicine, energy, and environmental protection. While the anthraquinone oxidation process has traditionally dominated industrial H₂O₂ production, its complexity and high pollution levels present significant challenges. In response, alternative methods such as electrochemical, photochemical, and photoelectrochemical pathways have emerged, providing greener and more sustainable solutions. These innovative approaches leverage only water, oxygen, and solar or electrical energy, positioning them as viable substitutes for the energy-intensive anthraquinone process. This review delves into the latest advancements in H₂O₂ production through the twoelectron oxygen reduction reaction (2e⁻ORR), twoelectron water oxidation reaction (2e⁻WOR), and the synergistic two-channel pathway (2e⁻ORR + 2e⁻WOR) in (photo)electrochemical systems, focusing on reaction pathways. It discusses underlying mechanisms, evaluation parameters, and the design of high-performance catalysts for on-site H₂O₂ production in environmental applications. Recent developments in advanced (photo)electrocatalysts over the past five years are highlighted, including key design strategies that enhance catalytic performance. The review also addresses future challenges and prospects in catalyst design and practical environmental applications of (photo)electrochemical systems for H₂O₂ production, serving as a valuable reference for researchers in the field.