Molecular engineering of gCN-based multifunctional photocatalysts via in situ covalent modification

Abstract

The utilization of semiconductor graphitic carbon nitride (gCN) for organic pollutant degradation represents an eco-friendly remediation. Presently, the focus of modification strategies for gCN primarily revolves around element doping, heterojunctions, and morphology, with little attention given to embellishing its intrinsic framework. Herein, a novel gCN-based privileged photocatalyst was established through controllable nitrogen–hydrogen bond addition/elimination and acylation reactions. Compared to pristine gCN, structurally decorated gCN-A exhibits a larger specific surface area, an extended visible light response range, and a narrow bandgap, which is beneficial for accelerating photon-generated carrier separation and facilitating stable electron migration. Meanwhile, gCN-A demonstrates moderate to strong degradation performance against 5 different organic pollutants, particularly rhodamine B (98.54%/6 min) and tetracycline (87.86%/10 min). ˙O₂⁻ was validated as the principal reactive species in organic contamination removal by electron spin resonance and scavenger experiments. Encouragingly, among the three antibacterial bioassays, gCN-A displays the best inhibitory performance against Pseudomonas syringae pv. actinidiae (100%), while also degrading the corresponding antimicrobial. Theoretical calculations revealed that modifying the nitrogen–hydrogen bonds in gCN alters electron cloud density distribution and promotes electron–hole separation. Overall, the current study provides a promising perspective on constructing multifunctional photocatalysts for degrading contaminants and inactivating pathogens through covalent modification.