Controllable fabrication of Ag/ZnO/g-C3N4 nanofiber heterojunctions for enhanced photocatalytic water disinfection

Abstract

With the accelerated development of urbanization, it is urgent to develop new green and effective fungicides for water disinfection, which can effectively sterilize without causing bacterial drug resistance and environmental burden. In this work, the new ternary nanofiber (NF) heterojunctions, Ag/ZnO/g-C₃N₄ (Ag/ZCN), with high specific surface area were controllably fabricated through the photodeposition of different amounts of Ag quantum dots on electrospun ZCN NFs. Ag/ZCN with 6 wt.% Ag was found to exhibit the highest antibacterial activity superior to that of ZCN and ZnO NFs, which completely killed E. coli or S. aureus within 30 min under solar light. Moreover, it maintained high stability during four consecutive photocatalytic cycles. The photocatalytic Z-scheme charge transportation mechanism of Ag/ZCN was confirmed through structure characterization and free radical capture experiments. It was verified that the active oxygen substances such as ·OH, ¹O₂, and a certain amount of ·O₂⁻ were mainly produced in the photocatalytic sterilization process. Therefore, the Z-scheme NF heterojunction Ag/ZCN has great application potential in actual environmental water disinfection.