Bi ₂O ₂CO ₃/BiOI photocatalysts with heterojunctions highly efficient for visible-light treatment of dye-containing wastewater

Bi ₂O ₂CO ₃/BiOI composites were fabricated at room temperature for the first time by a facile method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (UV-vis DRS), and nitrogen adsorption-desorption techniques were employed to characterize the physiochemical properties of the composites. The photocatalytic activities of Bi ₂O ₂CO ₃, BiOI, and Bi ₂O ₂CO ₃/BiOI were evaluated through the photocleaning of wastewater which contained rhodamine-B, methylene blue, crystal violet, or a mixture of them under visible-light irradiation (λ ≥ 420 nm). The photocatalytic activity of Bi ₂O ₂CO ₃/BiOI is much higher than that of its components. Moreover, the composite shows good photostability and recyclability. The excellent catalytic efficiency of the Bi ₂O ₂CO ₃/BiOI composite is deduced closely related to Bi ₂O ₂CO ₃/BiOI heterojunctions whose presence is generally regarded to be a favorable factor for the separation of photogenerated electrons and holes. Moreover, ·OH was found to be the main active species for the photocatalytic interactions. The catalyst shows potential application in the treatment of dye-containing wastewater.