Cadmium sulphide quantum dots sensitized hierarchical bismuth oxybromide microsphere with highly efficient photocatalytic activity

Abstract

Cadmium sulphide (CdS) quantum dots (QDs) sensitized that hierarchical bismuth oxybromide (BiOBr) photocatalysts were synthesized via a facile solvothermal approach for the first time, which were characterized by XRD, XPS, SEM, TEM, PL, and UV–vis DRS spectra. The photocatalytic activities were evaluated by the decomposition of methyl orange (MO) under visible light irradiation with commercial TiO2 Degussa P25 as reference. The results revealed that CdS–BiOBr photocatalysts had strong light absorption in the visible light region compared with pure BiOBr. All CdS–BiOBr photocatalysts possessed higher photocatalytic activity than pure BiOBr and Degussa P25 under the visible light irradiation. The highest activity was obtained by 2%CdS–BiOBr. The enhanced photocatalytic performances were attributed to the matched band potentials of CdS QDs and BiOBr, which resulted in the efficient separation of photogenerated electron–hole pairs. Based on the experimental results, a reasonable photocatalytic mechanism over CdS–BiOBr photocatalysts was proposed. And the photodegradation of MO are associated with O2- radicals and the photogenerated holes on the valance bands of CdS QDs and BiOBr.