Thickness Modification of BiOBr Nanosheets by Sn-TiO2 for Enhanced Photocatalytic Degradation of Antibiotics

Modification of morphological engineering to enhance photocatalytic activity has been considered an effective strategy. However, effective modification of the catalyst nanosheet thickness remains a difficult challenge to control. Here, we have synthesized Sn-TiO2/BiOBr composite photocatalysts by a one-pot method. With the addition of Sn-TiO2, the flakes of BiOBr gradually became thinner, resulting in more surface reaction site, and Sn-TiO2 clearly increased the adsorption capacity of the composite catalyst. The degradation efficiency of the prepared Sn-TiO2/BiOBr (the atomic ratio of titanium/bismuth 1:1) was 98% and 80% for TC-HCl and CIP, respectively, showing good photocatalytic performance. Furthermore, the radical trapping experiments revealed that h+ and •O2– play an important role in the Sn-TiO2/BiOBr system. Photoelectrochemical tests and photoluminescence confirm that the thin sheets can significantly improve carrier migration efficiency in Sn-TiO2/BiOBr heterojunctions. Finally, the degradation mechanism of the Sn-TiO2/BiOBr system was elucidated using UV-DRs and Mott–Schottky curves. Experimental analysis shows that modulating the thickness of BiOBr nanosheets with Sn-TiO2 can promote the exposure of surface reaction sites, can enhance their light adsorption ability and carrier mobility, and is a promising method for improving photocatalytic efficiency.