Single-atom dispersed Zn-N3 active sites bridging the interlayer of g-C3N4 to tune NO oxidation pathway for the inhibition of toxic by-product generation

• Single-atom dispersed Zn-CN with 37.0 wt% Zn-load amount was prepared. • Single Zn atoms bridged the interlayer of g-C 3 N 4 to form Zn-N 3 active sites. • Single Zn atoms induced O 2 and NO to fabricate the Zn-O 2 -NO structure. • Single Zn-CN catalyst showed favorable NO oxidation but low toxic NO 2 generation. Photocatalysis is regarded as one of the most promising methods for removing low concentrations of nitrogen oxides (NO x ) discharged from mobile sources, but its low activity and secondary contamination with harmful by-products restrict its practical implementation. Herein, we introduced single Zn atoms into the interlayer of g-C 3 N 4 prepared through a simple pyrolysis method with an ultrahigh loading amount of 37.0 wt% (10.2 at%). Zn-N 3 bridging structure is created by single atomic scattered Zn atoms connecting with three N atoms of two layers of g-C 3 N 4 , which enhance visible light absorption and electron-hole pairs’ separation. The introduced single Zn atom induced the adsorbed O 2 and NO to fabricate the Zn-O 2 -NO structure, which facilitated the dissociation of O 2 and the direct formation of nitrate from NO, tuning NO oxidation pathway and resulting in increased NO oxidization (49%) but low toxic NO 2 generation (2.6%). This current work introduces a novel approach to fabricating single-atom catalysts for highly effective environmental remediation and secondary pollution control.