Synthesis of Bi2O2CO3/Bi2S3 hierarchical microspheres with heterojunctions and their enhanced visible light-driven photocatalytic degradation of dye pollutants.

Bismuth subcarbonate (Bi2O2CO3) microspheres were synthesized by a simple hydrothermal method using bismuth citrate and sodium hydrogen carbonate as precursors. Furthermore, through a facile ion exchange method between the Bi2O2CO3 microspheres and thioacetamide (TAA), bismuth subcarbonate/bismuth sulfide (Bi2O2CO3/Bi2S3) heterojunctions were fabricated. The structures and morphologies of the Bi2O2CO3 and Bi2O2CO3/Bi2S3 products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photocatalytic activities of the products were evaluated by decomposing rhodamine B (RhB) under visible light irradiation. In contrast with Bi2O2CO3, the Bi2O2CO3/Bi2S3 heterojunctions showed enhanced visible light photocatalytic properties. In addition, the effect of ion exchange reaction time on the photodegradation quality was studied, and the mechanism of the enhanced photocatalytic properties was proposed.