A Review of Graphitic Carbon Nitride in Photocatalysts: Mechanisms, Synthesis, and Modification

Graphitic carbon nitride (g-C₃N₄) is a nonmetalic semiconductor photocatalytic material that has attracted widespread attention in the field of photocatalysis owing to its advantages, including abundant raw material sources, environmental friendliness, good cyclic stability, and ease of structural control. Currently, various methods are available for its preparation, including thermal polymerization, template-assisted synthesis, solvothermal synthesis, and chemical vapor deposition. By adjusting parameters such as pyrolysis temperature and time, the morphology of g-C₃N₄ can be effectively controlled. However, pure g-C₃N₄ still faces challenges, including high carrier recombination rates and limited utilization of visible light, resulting in relatively low photocatalytic activity. To overcome these limitations, various modification strategies have been studied extensively and analyzed the pathways for source modification on the basis of this mechanism. It outlines mainstream preparation methods and recent advances in modification research, evaluating the strengths and limitations of different strategies. Drawing on recent case studies, this discussion examines the advantages and constraints of various synthesis approaches, and links modification strategies to their respective application fields. Finally, future research directions for enhancing photocatalytic performance are proposed, aiming to provide theoretical insights and technical support for further research and practical applications of this material in photocatalysis.