Enhanced photocatalytic activity of g-C3N4 2D nanosheets through thermal exfoliation using dicyandiamide as precursor

Abstract g-C3N4 has received extensive attention because of its good chemical stability and environmental friendliness. Since g-C3N4 prepared from various precursors had different photocatalytic activities, g-C3N4 materials marked as U-gCN, D-gCN and M-gCN were synthesized from various precursors of urea, dicyandiamide and melamine, respectively. The D-gCN and M-gCN with smaller surface area were heated again to obtain exfoliated g-C3N4 with 2D nanosheet morphology and larger specific surface area named D-gCN-L and M-gCN-L, respectively. The synthesized bulk g-C3N4 and g-C3N4 2D nanosheets were characterized by XRD, SEM, BET, PL, UV–Vis diffuse reflectance spectroscopy, XPS, zeta potential and TG. The photocatalytic degradation of methylene blue (MB) was carried out on U-gCN, D-gCN, M-gCN, D-gCN-L and M-gCN-L, and D-gCN-L shows the highest photocatalytic degradation performance because of its larger specific surface area, lower electron-hole recombination and wide light absorption range.