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.