Functional group defect design in polymeric carbon nitride for photocatalytic application

Defects are conventionally considered as the active sites in heptazine-based polymer melon (also known as graphitic carbon nitride, g-C3N4) for photocatalysis and are rationally incorporated for improving the intrinsic photocatalytic ability. The rise of group functionalized g-C3N4 based on defect engineering has set off a new wave of research in recent years, especially in photocatalysis. In this review, the recent process in functional group defect strategies to design high-efficiency g-C3N4-based photocatalysts, including cyanamide/cyano moiety, urea group, oxygen-containing groups (—OH, —COOH), and aromatic motifs, has been strictly analyzed so as to inspire critical thinking about the efficient methodology for the rational design of polymeric photocatalysts. The applications of the group functionalized g-C3N4 in photocatalytic water splitting, CO2 reduction, H2 evolution, ammonia synthesis, H2O2 production, and disinfection are summarized. The current challenges and future promising applications of the group functionalized g-C3N4 materials for advanced catalysts are also discussed.