Photodegradation of Rhodamine B on Sulfur Doped ZnO/TiO2 Nanocomposite Photocatalyst under Visible-light Irradiation

Sulfur doped ZnO/TiO2 nanocomposite photocatalysts were synthesized by a facile sol-gel method. The structure and properties of catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffusive reflectance spectroscopy (DRS) and N-2 desorption-adsorption isotherm. The XRD study showed that TiO2 was anatase phase and there was no obvious difference in crystal composition of various S-ZnO/TiO2. The XPS study showed that the Zn element exists as ZnO and S atoms form SO42-. The prepared samples had mesoporosity revealed by N-2 desorption-adsorption isotherm result. The degradation of Rhodamine B dye under visible light irradiation was chosen as probe reaction to evaluate the photocatalytic activity of the ZnO/TiO2 nanocomposite. The commercial TiO2 photocatalyst (Degussa P25) was taken as standard photocatalyst to contrast the prepared different photocatalyst in current work. The improvement of the photocatalytic activity of S-ZnO/TiO2 composite photocatalyst can be attributed to the suitable energetic positions between ZnO and TiO2, the acidity site caused by sulfur doping and the enlargement of the specific area. S-3.0ZnO/TiO2 exhibited the highest photocatalytic activity under visible light irradiation after Zn amount was optimized, which was 2.6 times higher than P25.