Key factors in improving the synthesis and properties of visible-light activated g-C₃N₄ for photocatalytic hydrogen production and organic pollutant decomposition

Of current interest is visible-light activated g-C₃N₄, owing to its unique physicochemical properties for the photocatalytic H₂ production and pollutant remediation. In this research, the synthetic procedures, physicochemical properties, and major approaches to overcome the intrinsic drawbacks of g-C₃N₄ are reviewed. Of different synthesis procedures for GCN, thermal polymerization is recommended with advantages such as simplicity, economic, and high yield. Element doping, as a facile method, can modify g-C₃N₄ structure and improve its performance in the photocatalytic evolution of H₂ which is significantly increased from 208 µmol h⁻¹ g⁻¹ for bare g-C₃N₄ to 5128 µmol h⁻¹ g⁻¹ for P-doped g-C₃N₄. Ammonium salts can be effectively used for the synthesis of g-C₃N₄ nanosheets and element doping simultaneously. Vacancy defect plays an important role in the improvement of the photocatalytic activity. Compared to custom photocatalysis and electrocatalysis, photoelectrocatalysis is highly promising for pollutant decontamination due to the effective separation of charge carriers.