Fabrication of CsPbBr3 nanocrystals/Bi2MoO6 nanosheets composites with S-scheme heterojunction for enhanced photodegradation of organic pollutants under visible light irradiation

Abstract

Semiconductor photocatalysts can eliminate environmental pollution, especially water pollution. In this study, novel CsPbBr3 nanocrystals/Bi2MoO6 nanosheet composites were successfully fabricated via hydrothermal method together with electrostatic self-assemble process. The formation of S-scheme heterojunction, migration of photogenerated carriers and photocatalytic reaction mechanism were elaborated by means of density functional theory (DFT) calculation, In-situ irradiated X-ray photoelectron spectroscopy (XPS) and other characterization techniques. This scheme not only solved the problem of poor photogenerated carrier migration and separation efficiency of Bi2MoO6 based photocatalyst, but also broadened the photo-response range. For the emerging photocatalyst CsPbBr3, the surface morphology of the synthesized composite was also conducive to improve its’ chemical stability. Compared to other specimens, the CsPbBr3/Bi2MoO6 5 wt% (BC5%) composite sample showed the optimal photocatalytic activity and the Rhodamine B (RhB) degradation over it attained 95.8% under visible light irradiation for 90 mins. Additionally, the degradation performances of RhB in different solution environments such as catalyst dosage, pollution concentration, pH, and reaction temperature were thoroughly investigated. Especially, the photocatalytic activity of BC5% composite sample was also evaluated via biotoxicity experiments. This work would provide a successful experience for devising and realizing highly efficient photocatalysts in the future.