Facile ion-exchange construction of Bi4Ti3O12/BiOBr heterojunctions for efficient charge transport: Mechanism and applications

The pure Bi 4 Ti 3 O 12 with a flower-like morphology followed by the controlled growth of BiOBr through a simple room-temperature ion-exchange process. This strategy enables the Aurivillius-type Bi 4 Ti 3 O 12 and BiOBr share the (Bi 2 O 2 ) 2+ layers at the interface, which demonstrate by first-principles calculations and in-situ XPS. Benefiting from the coherent interface and type-II charge transfer pathway, the heterojunctions exhibited significantly enhanced charge separation, transport efficiency and significantly increasing the yield of photocatalytic reactive species. Thereby, the optimized sample achieved 91.3% degradation of 40 ppm tetracycline hydrochloride, 89.6% degradation of 15 ppm ciprofloxacin within 30 min,and 90.6% sulfamethoxazole after 120 min.Demonstrating superior photocatalytic performance compared to the previously reported analogous photocatalysts in recent years with respect to antibiotic degradation. The degradation efficiency of the as-prepared photocatalyst with a reduction of only 6% after three cycles. Therefore, this simple and scalable strategy of constructing coherent heterojunctions of Bi 4 Ti 3 O 12 /BiOBr exhibits immense potential for practical applications.