Construction of novel Z-scheme CDs/Bi4O5Br2/ATP heterojunction for photocatalytic degradation of ciprofloxacin

Bi4O5Br2 material exhibits excellent performance in photocatalytic degradation of antibiotics, but high recombination rate of photoexcited electron-hole pairs limits its photocatalytic activity. Attapulgite (ATP) is an excellent candidate for load type catalyst due to its larger specific surface area. As a new type of carbon-based nanomaterials, carbon dots (CDs) have important application prospects in catalysis and other fields. Herein, Zscheme CDs/Bi4O5Br2/ATP composite photocatalyst loaded with varied proportions of CDs was synthesized by dynamic adsorption method, which demonstrated excellent photocatalytic degradation performance by lowering the recombination rate of photoexcited electron-hole pairs. Ciprofloxacin degradation efficiency by 3 wt% CDs/ Bi4O5Br2/ATP can reach up to 90% within 120 min under simulated sunlight, in addition, the 3 wt% CDs/ Bi4O5Br2/ATP composite photocatalyst has good stability. As a result, our research helps to prepare highefficiency Z-scheme heterojunction and contributes to study the degradation of antibiotics in the aquatic environment.