Novel AgCl nanoparticles coupling with PbBiO₂Br nanosheets for green and efficient degradation of antibiotic oxytetracycline hydrochloride under visible-light irradiation

In this work, novel Ag/AgCl/PbBiO₂Br photocatalysts were synthesized via a hydrothermal and in situ photoreaction method. The microstructure, morphology, composition, electrochemical, and optical properties of the synthesized catalysts were investigated by multiple techniques. The obtained Ag/AgCl, PbBiO₂Br, and Ag/AgCl/PbBiO₂Br composites were evaluated via degradation of oxytetracycline (OTC) hydrochloride antibiotic under visible-light irradiation. The results show that the Ag/AgCl/PbBiO₂Br composites are composed of Ag/AgCl nanoparticles (NPs) and PbBiO₂Br nanosheets. The Ag/AgCl/PbBiO₂Br (20.4%) composite exhibits the highest visible-light absorption and best photogenerated charge separation efficiency. The photocatalytic degradation experiments show that all Ag/AgCl/PbBiO₂Br composites exhibit an enhanced degradation activity under visible-light irradiation, and maintain good stability in the photocatalytic process. The Ag/AgCl/PbBiO₂Br (20.4%) composite has the highest degradation activity, which is 1.82 and 2.11 times higher than that of Ag/AgCl and PbBiO₂Br, respectively. The enhanced photocatalytic activity of Ag/AgCl/PbBiO₂Br can be mainly attributed to the fact that the loading of Ag NPs on the surface of the AgCl promotes the separation efficiency of photoinduced charge and enhance the visible-light absorption. Additionally, active species trapping experiments confirm that superoxide radicals ($\cdot {\text{O}}_2^{-}$), Cl⁰ and holes (h⁺) play an very important role in the degradation process.