Dye Decolorization Under Visible Light Irradiation Using Bismuth Subcarbonate

Commercially available bismuth subcarbonate (Bi2O2CO3) was treated with nitric acid and the surfactant cetyltrimethylammonium bromide. The treated catalysts exhibited enhanced photocatalytic activity compared to pure Bi2O2CO3 in the decolorization of rhodamine B (RhB) under visible light irradiation. The absorbance at 554 nm gradually decreased over time and disappeared completely within 80 min. The crystal structure, morphology, and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The improved photocatalytic activity of the treated catalysts was attributed to partial carbonate removal and the formation of Bi5+ species. Scavenger experiments indicated that superoxide radicals (·O2−) and photogenerated holes (h+) played significant roles in the photocatalytic decolorization of RhB.