Construction of single-atom Ag embedded O, K co-doped g-C3N4 with enhanced photocatalytic efficiency for tetracycline degradation and Escherichia coli disinfection under visible light

Photocatalytic technique has been widely accepted as a promising and effective candidate for eliminating antibiotic and pathogen pollutants in aquatic environment. Herein, a novel O, K co-doped g-C3N4 photocatalyst embedded with single-atom Ag (denoted as Ag/OKCN) was successfully constructed to achieve the enhanced photocatalytic degradation and disinfection efficiency under visible light irradiation. The optimal Ag/OKCN-6 could eliminate 80.4 % of tetracycline (TC) within 60 min with a rate constant of 0.0259 min−1, which was 4.98 times of pristine g-C3N4. Meanwhile, Ag/OKCN-6 could also completely inactivate>7-log CFU·mL−1 of Escherichia coli (E. coli) by efficient disruption of cell membranes. The synergistic effect of O, K co-doping and single-atom Ag embedding contributed to an extended light response, preeminent separation and transfer of photoexcited charges, prolonged carrier lifetime as well as ameliorative hydrophilicity, which was conducive to the excellent photocatalytic performance. Radical trapping and electron spin resonance (ESR) experiments validated that superoxide radicals (•O2−) were crucially responsible for the superior photocatalytic activity. This work provides a facile route to construct multi-strategy modified g-C3N4-related photocatalysts for efficiently eliminating aquatic environmental pollutants.