Environment-friendly Ag/CDots/g-C3N4 photocatalysts: Remarkably enhanced photocatalytic tetracycline degradation in visible light

The g-C3N4 was widely used in water purification recently. However, the further application was severely suppressed because of the rapid electron-hole recombination and low visible-light utilization efficiency. Herein, we fabricated the three-component Ag/CDots/g-C3N4 nanocomposites which effectively enhanced the photo degradation of tetracycline (TC) under visible light irritation (similar to 93.4% in 60 min), compared with Ag/g-C3N4 (similar to 76.1%), CDots/g-C3N4 (similar to 63.8%) and g-C3N4 (similar to 44.2%). The morphology, structural and compositional information of Ag/CDots/g-C3N4 was observed as well as the optical and electric properties, and the photocatalytic mechanism was revealed in detail. The addition of CDots could effectively increase light absorption efficiency, accelerate electron transfer and separation, and act as an electron-reservoir center. The presence of Ag had increased electron density via SPR effect, further enhancing the photocatalytic performance. The Ag/CDots/g-C3N4 also showed great stability and reusability with ignorable change in five recycle. Besides, the toxicity assessment proved the good biocompatibility and low cytotoxicity of Ag/CDots/g-C3N4. The study indicated that the successful synthesis of Ag/CDots/g-C3N4 paved way to water purification.