CTAB-assisted construction of 3D flower-sphere S-scheme Bi12O17Br2/Bi4O5Br2 heterojunction with enhanced visible-light photocatalytic performance

In this study, novel 3D flower-sphere S-scheme Bi12O17Br2/Bi4O5Br2 heterojunction was successfully synthesized at room temperature through a facile co-precipitation method. As the morphology controlling reagent and bromine resource, cetyltrimethylammonium bromide (CTAB) surfactant played significant roles in Bi12O17Br2/Bi4O5Br2 crystal growth and heterostructure construction. The BB-10 (Bi12O17Br2/Bi4O5Br2, pH = 10) heterojunction with hierarchical heterostructure presented excellent photocatalytic activity under visible light for antibiotic tetracycline (TC), malachite green (MG) and methyl violet (MV) removal and the photodegradation efficiency could reach 97.3%, 90.4% and 87.5%, respectively. In addition, when CTAB was replaced by cetyltrimethylammonium chloride (CTAC), the as-obtained 2D flower-like type-I BCB-10.5 (BiOCl/Bi4O5Cl2, pH = 10.5) heterojunction also exhibited outstanding visible-light photocatalytic activity for the removal of TC, MG and MV. Greatly enhanced photocatalytic activity owed to synergistic effects including unique hierarchical morphology, large specific surface area and suitable band structures. According to the active species trapping experiments, feasible photocatalytic mechanisms were proposed. [Display omitted] •S-scheme heterojunction of Bi12O17Br2/Bi4O5Br2 was synthesized at room temperature.•Dispersed flower-sphere morphology of the heterojunction benefits charge transfer.•S-scheme heterojunction prolonged lifetime of carriers with stronger redox ability.•The heterojunction exhibited excellent photoreactivity for TC, MG and MV removal.