Visible-light photodegradation of sulfamethoxazole (SMX) over Ag-P-codoped g-C3N4 (Ag-P@UCN) photocatalyst in water

Ag-decorated phosphorus doped graphitic carbon nitride (Ag-P@UCN) nanocomposite was successfully synthesized. Ag nanoparticles (average size = 15 nm) were well-crystalline and uniformly dispersed on the P doped g-C3N4 (P@UCN) surface. Nano-Ag particles enhanced light absorption and acted as electron sink to capture photogenerated electrons, and promoted the separation of photo-induced charge. Results showed greater than 99% of sulfamethoxazole (SMX) removal within 30 min under visible light irradiation. The photodegradation rate of SMX over Ag-P@UCN was similar to 4 and 7 times faster than that on pristine g-C3N4 (UCN) and P@UCN, respectively. Ag-P@UCN was stable and could be reused for at least 6 cycles without losing photocatalytic activity. Reactive oxygen species played a significant role in the photodegradation of SMX. Overall, a new scheme to synthesize heterojunction photocatalysts, exemplified by Ag-based nanomaterials, for the heterogeneous photodegradation of organic contaminants under visible light was attained.