Synergetic promotional effect of dual oxygen vacancies and 2D/2D TiO2/BiOBr S-scheme heterostructure for boosted photocatalytic oxytetracycline removal

Novel 2D/2D TiO 2 /BiOBr (TOB- x , x represented the molar ratio of TiO 2 /BiOBr) heterostructures with dual oxygen vacancies were fabricated via an in-situ hydrothermal approach. Owing to the construction of p-n heterostructure and strong interface interaction, a S-scheme charge transfer path was formed, which facilitated efficiency separation and transfer of charge and retained strong redox capacities of photoexcited electrons and holes. Simultaneously, the introduction of oxygen vacancies induced strong photoabsorption, improving the light harvesting capacity. The oxytetracycline (OTC) degradation efficiencies over TOB-0.05 and TOB-0.1 were significantly improved relative to those of single components. The TOB-0.1 photocatalyst displayed the best photocatalytic activity, which was 3.75 and 1.76 times higher those of TiO 2 -Vo and BiOBr-Vo, respectively. Furthermore, we also examined the effects of pH, ions, and water matrixes on OTC conversion of TOB-0.1, and investigated the photocatalytic degradation mechanism. This work provides a useful guideline for constructing high-efficiency photocatalysts for wastewater treatments by combining 2D/2D heterojunction and dual-defect engineering.