Construction of Z-scheme heterojunction by coupling Bi₂Sn₂O₇ and BiOBr with abundant oxygen vacancies: Enhanced photodegradation performance and mechanism insight

Promoting charge migration and enhancing redox ability of photogenerated carriers are important for the development of highly efficient semiconductor-based photocatalyst. Here, BiOBr/Bi₂Sn₂O₇ heterojunction with oxygen vacancies (OVs) was constructed by homogeneously depositing Bi₂Sn₂O₇ nanoparticles on the Vo-BiOBr surface. The experimental results manifested that Vo-BiOBr/Bi₂Sn₂O₇ displayed better performance for rhodamine B, ciprofloxacin, and tetracycline degradation than counterparts without OVs. The characterization results proved OVs played the essential role for enhanced performance via improving the separation efficiency of charge carriers, increasing the visible light harvest, and lowering conduction band position. Moreover, mechanism study revealed that an inner electric field was built at the interface, leading to a Z-scheme path of photogenerated electron. This study provided an efficient strategy for designing highly efficient photocatalyst for solving environmental pollution.