Nanocomposite of Cu-TiO_2-SiO_2 with High Photoactive Performance for Degradation of Rhodamine B Dye in Aqueous Wastewater

摘要

The nanocomposite of Cu-TiO_2-SiO_2 photocatalyst have been prepared by a sol-gel method, which is used for the degradation of Rhodamine B (RB) as a probe that is notorious organic compound present in dyes wastewater. Morphological and structural characteristics of the CuTiO_2-SiO_2 nanocomposite were studied with low temperature N_2 adsorption (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectroscopy (DRS). The Fourier transformed infrared spectroscopy (FT-IR) analysis shows the enhanced chemical bonding of O-Ti and O-Ti-O after the composition of Cu and SiO_2 species into TiO_2. It is found that the Cu-TiO_2-SiO_2 nanocomposite exhibits much higher photocatalytic activity under both UV light and visible light irradiation as compared with that over commercial titania (Degussa P25) toward the dyes wastewater containing RB. The photodegradation rate of RB (5 mg/L) can reach above 95.0% under sunlight after 3 h. The addition of SiO_2 not only inhibites the crystal growth and anatase-torutile transformation of TiO_2 nanocatalyst, but also enhances the adsorption of organic compounds. Cu-doping extends the light response to the visible region. Synergetic effects between Cu-SiO_2 and TiO_2 have been investigated, which provides a good way and material in the degradation field of dyes wastewater.