Boosting visible-light photocatalytic NO removal by non-intrinsic oxygen vacancies in graphitic carbon nitride

Modifying photocatalysts for effective NO removal has profound implications for environmental protection. In this work, a novel g-C3N4 containing non -intrinsic oxygen vacancies (VO-CN) is synthesized via a facile oxygen pre -doping followed by elimination. Compared to pristine g-C3N4, VO-CN exhibits remarkably enhanced visiblelight photocatalytic activity, increasing NO removal by 54.3%, with high NO3- selectivity. This photocatalytic enhancement is attributed to the non -intrinsic oxygen vacancies introduced in Vo-CN. As comprehensively revealed by experimental characterizations coupled with density functional theory (DFT) calculations. The results show that the midgap state generated in the VO-CN electronic band structure accelerates photogenerated electron -hole separation. Additionally, the unique surface structure of VO-CN provides favorable channels for carrier migration while enhancing O2 and NO adsorption. Consequently, the markedly improved generation of reactive oxygen species by Vo-CN promotes highly efficient NO removal. This work provides novel insights into designing high-performance g-C3N4-based photocatalysts for eliminating hazardous NO pollutants.