Construction of novel double S-scheme TiO_2-x/BiOCl/BiCl₃Br-CTA nanocomposites with quantum dot size for the photocatalytic degradation of pollutants

In this study, TiO_2-x/BiOCl/BiCl₃Br-CTA (T_OVBBOC) nanocomposites, in which CTA denotes cetyltrimethylammonium cation, were fabricated through a facile hydrothermal method. The nanocomposites were investigated for photocatalytic degradation of azithromycin (Azi), tetracycline (TC), methyl orange (MO), fuchsine (FS), and rhodamine B (RhB) upon visible light. The photocatalytic efficiencies of T_OVBBOC-2 were 37.2, 15.3, 20.2, 13.8, and 5.59 times higher than TiO_2-x (T_OV) and 18.1, 22.1, 16.6, 20.3, and 14.2 folds larger than BiOCl/BiCl₃Br-CTA for the degradations of Azi, TC, MO, FS, and RhB, respectively. Furthermore, the cycling tests confirmed that the T_OVBBOC-2 nanocomposite displayed a high photostability. The significant photocatalytic performance of T_OVBBOC-2 heterojunction was mainly attributed to the increased visible-light absorption and a lower recombination rate of photogenerated charges. A photo-removal mechanism on the T_OVBBOC-2 photocatalyst was also proposed based on band position and radical trapping tests. Importantly, the biocompatibility of the TC solution after treating over the T_OVBBOC-2 nanocomposite was studied via the growth of wheat seeds. The current research offered a promising route for fabricating an effective visible-light-driven material for environmental remediation.