Efficient surface reaction pathways in metal-free organic semiconductors for practical photocatalytic hydrogen peroxide production.

Hydrogen peroxide (HO) is a versatile oxidant widely used in pharmaceuticals, environmental protection, and chemical manufacturing. However, conventional HO production relies on energy-intensive processes and costly metal-based catalysts, raising economic and environmental concerns. As a sustainable alternative, photocatalytic HO synthesis harnesses solar energy, water, and oxygen under mild conditions. This review summarizes recent advancements in the development of metal-free organic semiconductors for photocatalytic HO generation. Notably, it delves into novel surface reaction mechanisms, including anthraquinone (AQ) intermediate, peroxy acid intermediate, bipyridine intermediate, and dual channel synergistic mechanisms for optimizing photocatalyst performance. This review also umderscores the critical role of advanced characterization techniques, including in-situ characterizations and computational simulations, in elucidating structure-property relationships and monitoring real-time catalytic processes. By presenting novel strategies for material modification and exploring potential device-level applications, the review aims to inspire further research and facilitate the industrial implementation of photocatalytic HO production, thereby advancing sustainable chemical manufacturing.