Metal‐Free Modification Overcomes the Photocatalytic Limitations of Graphitic Carbon Nitride: Efficient Production and In Situ Application of Hydrogen Peroxide.

Graphitic carbon nitride (g‐C3N4) assisted photocatalytic production of hydrogen peroxide (H2O2 has already attracted the interest of many researchers due to its environmental sustainability. Nevertheless, the inherent drawbacks of g‐C3N4 limit its progress. Metal‐free modification strategies, including nanostructure design, defect introduction, doping, and heterojunction construction, have been developed to improve the efficiency of g‐C3N4 photocatalytic H2O2 production. Compared to metal modification, metal‐free strategies avoid the use of precious metals and the leaching of heavy metal ions, which have the advantages of good stability and environmental friendliness. However, a comprehensive review of H2O2 production from g‐C3N4 modified by metal‐free strategies is still lacking. This review first recaps the mechanism of photocatalytic H2O2 production by g‐C3N4, including photoexcitation, carrier separation and redox reactions. Then, the perspective advances in metal‐free modified g‐C3N4 photocatalysts are presented, with the special focus on the kernel connection between different strategies and mechanism based on the pivotal stages of H2O2 production. Subsequently, recent applications of g‐C3N4‐based photocatalysts for in situ generated H2O2, mainly including water purification and organic synthesis, are briefly discussed. Finally, the prospects of g‐C3N4‐based photocatalysts are envisioned with the hope that it will have “something to do” in the field of H2O2 production. [ABSTRACT FROM AUTHOR]