Enhanced Photocatalytic Antibiotic Micropollutants Removal Resulting From a Synergism Between Cu Single Atoms and Carbon Vacancies on Graphitic Carbon Nitride

Photocatalytic processes driven by visible-light irradiation offer a sustainable means of micropollutants removal from aquatic environments without the addition of reagents. In this study, an enhanced production of photogenerated carriers under visible light has been achieved using acidified graphitic carbon nitride (ag-C 3 N 4 ) modified with atomically dispersed Cu (Cu/ag-C 3 N 4 ), which serves as an efficient photocatalyst for treating antibiotic micropollutants. The optimized Cu/ag-C 3 N 4 system achieved >90% micropollutants removal efficiency within 30 min. A combination of experimental testing and density functional theory analysis has confirmed the formation of an active and stable CuN 3 configuration, generated by the incorporation of atomic Cu species at C vacancies that effectively modulates surface charge redistribution and enables charge separation. The photocatalytic degradation of micropollutants is promoted by photogenerated holes (h + ) in tandem with reactive oxygen species ( · OH $$ \cdotp \mathrm{OH} $$ , O 2 − · $$ {\mathbf{O}}_2^{-}\cdotp $$ , 1 O 2 ), where O 2 − · $$ {\mathrm{O}}_2^{-}\cdotp $$ and 1 O 2 species play dominant roles in the Cu/ag-C 3 N 4 system. The application of ultra-performance liquid chromatography–tandem mass spectrometry analysis has been used to identify possible degradation pathways and establish a synergistic degradation mechanism. This work provides a comprehensive understanding of heteroatom doping that enhances photocatalytic activity, offering a new strategy in designing highly efficient photocatalysts for treating micropolluted water.