In situ preparation of graphitic carbon nitride bonded with cyano groups for enhanced photocatalytic activity

Cyano groups have been successfully introduced on the backbone edge of g-C₃N₄ to fabricate nitrogen defects under mild conditions, which are derived from incomplete polymerization of g-C₃N₄ after BaCO₃ utilization. Characterization results indicate that the interfacial interaction between BaCO₃ and carbon nitride is playing a significant role for introducing cyano groups into g-C₃N₄. Cyano groups working as electron capture centers are proved to change the band gap of carbon nitride, reducing the recombination rate of electron-hole pairs and promoting charge separation. As expected, the hydrogen evolution rate of nitrogen-defect-modified carbon nitride is improved to 71.57 μmol h⁻¹, which is 13.5 times that of pristine C₃N₄. Meanwhile, the degradation efficiency of methyl orange is promoted (5 times that of pristine C₃N₄). This work is the first report on the fabrication of cyano-group-modified carbon nitride with BaCO₃ utilization, and opens a new door for further exploring environmental-friendly carbon nitrides on energy conversion.