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

Abstract

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.