Recent advances in structural modification on graphitic carbon nitride (g-C₃N₄)-based photocatalysts for high-efficiency photocatalytic H₂O₂ production

To date, extensively high demand for hydrogen peroxide (H₂O₂) has been predominantly supplied by the anthraquinone process for several worldwide applications, encompassing wastewater treatment, environmental remediation, and chemical synthesis. However, the compacted manufacturing, massive energy input and the release of tremendous wastes have restricted commercialization feasibility. Regards to mitigate such issues, the photocatalytic H₂O₂ production by utilizing g-C₃N₄ catalysts has endowed a greener, sustainable and promising alternative, considering that it involves water and oxygen as reactants in the present of sunlight as energy input. Herein, we have manifested a comprehensive overview of the research progress for g-C₃N₄-based semiconductors for photocatalytic H₂O₂ generation. This review has systematically elucidated state-of-the-art development of different modifications on g-C₃N₄ to unravel the fundamental mechanism of H₂O₂ evolution via oxygen reduction reaction (ORR) and water oxidation reaction (WOR). In addition, the contribution made by vacancy introduction, doping, heterogenization, and co-catalyst passivation with respect to photoefficiency enhancement have been clarified. Furthermore, the current challenges and perspective of future development directions on photocatalytic H₂O₂ production have also been highlighted. As such, g-C₃N₄ stands as the next step toward advancement in the configuration and modulation of high-efficiency photocatalysts.