‘Flower-like AgBr/CeO2 Z-scheme heterojunction photocatalyst with enhanced visible light photocatalytic and antibacterial activities

Abstract

The construction of Z-scheme heterojunctions is an effective method to enhance the photocatalytic activity of compounds. In this study, flower-like AgBr/CeO2 Z-scheme photocatalysts were synthesized by an in situ deposition–precipitation method. The AgBr mass fraction in the composites affected the photocatalytic performance. Notably, 40 wt%-AgBr/CeO2 exhibited optimal photocatalytic activity for the degradation of rhodamine B (RhB), methyl orange (MO), and tetracycline (TC) with final removal rates of 96%, 93.4%, and 77.8%, respectively. Following visible light irradiation for 180 min, 99.7% E. coli disinfection was achieved in the presence of this photocatalyst. After four cycles, 40 wt%-AgBr/CeO2 retained 65.0% photocatalytic activity for degrading RhB. Various analyses revealed that the dispersion of AgBr in the composites enhanced their optical properties. The 3D flower-like CeO2 provided a large contact interface and accelerated the transfer of photogenerated carriers. A Z-scheme heterojunction between AgBr and CeO2 afforded higher redox capacity and provided abundant Ce3+/Ce4+ couples with rich oxygen vacancies, facilitating the separation of photogenerated e−–h+ pairs and affording various active species (•O2−, •OH, and h+); therefore, 40 wt%-AgBr/CeO2 displayed excellent visible-light photocatalytic and antibacterial activities, and it could be utilized in complex wastewater treatment.