A BiOIO3/BiOBr n-n heterojunction was constructed to enhance the photocatalytic degradation of TC

Nowadays, heterojunction materials are of great interest in photocatalytic degradation studies of organic pollutants owing to their high separation efficiency from photogenerated carriers. In this study, BiOIO3/BiOBr n-n type heterojunctions were successfully synthesized and used for photocatalytic degradation of TC. Under visible light, the degradation rate of the 10%BiOIO3/BiOBr heterojunction reached 74.91% after 80 min irradiation, which was 26.79% and 22.67% higher than that of pure BiOBr and BiOIO3, respectively. The formation of BiOIO3/BiOBr n-n type heterojunction enhanced the light absorption ability, and the internal electric field formed between them accelerated the electron-hole pairs separation and transfer, thus enhancing the photocatalytic activity, which was confirmed by UV–Vis DRS, electrochemical and PL spectrum tests. Meanwhile, as confirmed by SEM and TEM, the BiOIO3/BiOBr heterojunction adheres face to face, and the large and tight contact area provides more channels for electron migration. Moreover, the active species that take part in the photocatalytic reaction were identified as ∙O2− and h+ by radical trapping experiments. According to the HPLC-MS test, the possible photocatalytic degradation pathways of TC were investigated. Finally, the charge transfer mechanism of BiOIO3/BiOBr n-n heterojunction is proposed. This study may offer a design pathway for constructing visible light responsive bismuth-based heterojunction materials and may also provide some ideas for solving the growing problem of antibiotic contamination.