Enhanced degradation of rhodamine B, tetracycline and carbamazepine by construction of a solar driven indirect Z-scheme AgI/Ag/Bi2O2CO3 nanosheets photocatalyst

The indirect Z-scheme AgI/Ag/Bi₂O₂CO₃ nanosheets photocatalysts were facilely constructed with Ag nanoparticles generated between AgI and Bi₂O₂CO₃ nanosheets through in situ photo-reduction process. The morphology, structure, chemical composition, optical and photo-electrochemical properties were characterized via various methods. Different organic pollutants, including Rhodamine B (RhB), Tetracycline (TC) and Carbamazepine (CBZ) were used to explore the photodegrading application of AgI/Ag/Bi₂O₂CO₃ nanosheets. AgI/Ag/Bi₂O₂CO₃ nanosheets exhibited highly improved photocatalytic activities than that of Bi₂O₂CO₃ nanosheets (BOC sheets), AgI/BOC sheets and AgI. The photocatalytic rates of RhB, TC and CBZ degradation on AgI/Ag/Bi₂O₂CO₃ nanosheets were 2.48, 1.31 and 7.61 times higher than that of BOC sheets, respectively. The as constructed indirect Z-scheme structure may be the main factor to increase the photocatalytic performance of AgI/Ag/Bi₂O₂CO₃ nanosheets, where Ag can act as charge transfer bridge accelerating the charge transfer and separation of the electrons and holes. Moreover, it may also result in higher oxidative holes in VB of Bi₂O₂CO₃ and more reductive electrons in CB of AgI. The photocatalytic mechanism on the AgI/Ag/Bi₂O₂CO₃ nanosheets was also discussed based on the trapping experiment results that ·O₂⁻ and h⁺ were the main radicals during photocatalytic reaction. The present study may provide a rational strategy to design highly efficient indirect Z-scheme photocatalyst for organic pollutants degradation.