Graphitic carbon nitride (g-C₃N₄) has developed into a useful photocatalyst because of its metal-free nature, variable electronic structure, and remarkable chemical stability. Nevertheless, low quantum efficiency, quick electron-hole recombination, restricted absorption of visible light, and a deficiency of surface-active sites continue to limit its practical use. To get beyond these intrinsic constraints, recent research has focused on advanced structural engineering and interface design, particularly Z-scheme heterojunctions and sustainable modification methods. This review focuses on the regulation of defect formation, heteroatom incorporation, and interfacial charge dynamics, microbial metabolites, and natural biomolecules. Additionally, it offers for the first time the latest developments in g-C₃N₄ alteration by biogenic synthesis. Focus is placed on the development of biogenic g-C₃N₄ and g-C₃N₄-based Z-scheme heterostructures, which exhibit improved performance in pollutant degradation and photocatalytic antibacterial applications, enhanced formation of reactive oxygen species (ROS), and excellent redox capacity. The mechanistic advancements, key structure-property connections, and major challenges associated with environmentally friendly synthesis are also described. Moreover, this work provides an outlook on sustainable, cost-effective, and high-efficiency g-C₃N₄ materials for next-generation environmental and biomedical applications. Future developments in g-C₃N₄-based photocatalysis will be on design functional materials and activity which is backed by theoretical modeling and operando diagnostics. Defect-engineered and atomically scattered g-C₃N₄ catalysts with higher charge separation and redox selectivity can be found more quickly by combining machine learning (ML) and density functional theory (DFT). Scalable, low-temperature synthesis methods, a methodical investigation of Z-scheme heterostructures, and thorough stability evaluations are necessary for future development in order to connect laboratory discoveries with practical environmental and energy applications.
Sindhav et al. (Fri,) studied this question.