One-step thermal polymerization synthesis of nitrogen-rich g-CN nanosheets enhances photocatalytic redox activity.

Graphitic carbon nitride (g-CN) has attracted enormous attention as a visible-light-responsive carbon-based semiconductor photocatalyst. However, fast charge recombination seriously limits its application. Therefore, it is urgent to modify the electronic structure of g-CN to obtain excellent photocatalytic activity. Herein, we reported a one-step thermal polymerization synthesis of nitrogen-rich g-CN nanosheets. Benefiting from the N self-doping and the ultrathin structure, the optimal CN-70 exhibits its excellent performance. A 6.7 times increased degradation rate of rhodamine B ( = 0.06274 min), furthermore, the hydrogen evolution efficiency also reached 2326.24 μmol h g ( > 420 nm). Based on a series of characterizations and DFT calculations, we demonstrated that the N self-doping g-CN can significantly introduce midgap states between the valence band and conduction band, which is more conducive to the efficient separation of photogenerated carriers. Our work provides a facile and efficient method for self-atom doping into g-CN, providing a new pathway for efficient photocatalysts.