Embedding defective tin oxide quantum dots into flake Bi4O5I2 for antibacterial and degradation by LED light irradiation

The construction of heterojunction structure has been widely proved to be a general strategy for photocatalytic removal of pollutants. In this paper, a novel point and plane embedded SnO2−x/Bi4O5I2 heterojunction containing oxygen vacancy was synthesized by simple thermal decomposition of SnO2−x/BiOI composite in a semi-closed crucible. The structure of SnO2−x/Bi4O5I2 was proved by TEM, HRTEM, BET, XPS and ESR. The SnO2−x/Bi4O5I2 catalyst successfully improved the photocatalytic performance in removing Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and tetracycline (TC), in contrast with individual SnO2−x and Bi4O5I2. Photocurrent and EIS results confirmed the high separation efficiency of electron and hole in composite. The active substance was identified by capture experiment, and combined with the energy band structure of the prepared photocatalyst, it was deduced that SnO2−x/Bi4O5I2 followed the double transfer mechanism. This study will furnish an efficient strategy to exploit tight heterojunction photocatalytic materials containing oxygen vacancy.