Construction of hierarchical FeIn2S4/BiOBr S-scheme heterojunction with enhanced visible-light photocatalytic performance for antibiotics degradation

Abstract

Constructing heterojunction provides a promising tactic to improve the photocatalytic efficiency of catalysts. In this paper, hierarchical FeIn2S4/BiOBr heterostructure photocatalysts were prepared by facile two step methods and applied to effectively remove ciprofloxacin (CIP) and tetracycline (TC) under visible light. Compared to single catalyst, FeIn2S4/BiOBr hybrids display significantly improved photocatalytic activity. Among the series, 6 wt% FeIn2S4/BiOBr shows the optimal photocatalytic performance, where the degradation efficiencies of TC and CIP are 3.15 and 2.88 times greater than pure BiOBr, respectively. Such an improvement could arise from the S-scheme heterojunctions and unique hierarchical structures, which brings stronger light absorption, higher photoexcited charge separation efficiency and superior redox ability. Furthermore, 6 wt% FeIn2S4/BiOBr composite exhibits excellent stability and reusability. Radical capture experiments and EPR analyses uncover that O2–, h+ and OH are primarily reactive substances during photocatalytic removal of TC. The products of TC were detected by LC-MS analyses and possible decomposition paths are proposed. Eventually, a possible photodegradation mechanism over FeIn2S4/BiOBr S-scheme heterojunction is proposed. These findings supply new perspective for the simple synthesis of S-scheme photocatalysts with promising applications in environment remediation.