Microwave-assisted synthesis of nanocomposite Ag/ZnO–TiO2 and photocatalytic degradation Rhodamine B with different modes

Abstract

By the microwave-assisted synthesis, the nano-composite Ag/ZnO–TiO2 was prepared under cetyl trimethyl ammonium bromide (CTAB). The composition, structure and morphology were well-characterized by X-ray diffraction (XRD), diffuse reflectance (UV–vis/DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and N2 adsorption–desorption measurement. The results showed that the product Ag/ZnO–TiO2 synthesized by microwave-assisted contained part ZnTiO3 and Zn2TiO4 excepting ZnO wurtzite, and silver species existing in Ag/ZnO–TiO2 was metaIlic Ag0. Compared with the Ag/ZnO–TiO2 synthesized by temperature-programed hydrothermal treatment, the product Ag/ZnO–TiO2 prepared by microwave-assisted method not only showed the improved morphology, and the BET specific surface area and pore volume were enlarged in varying degrees, but also had a stronger response in the visible area. Moreover, photocatalytic properties of the as-nanocomposites Ag/ZnO–TiO2 were tested by the different modes including ultraviolet, visible light, simulated sunlight and microwave-assisted irradiation photocatalytic degradation of Rhodamine B (RhB). The results showed that the photocatalytic activities of the product Ag/ZnO–TiO2 of microwave-assisted synthesis were much higher than that of P25, ZnO and other samples. In addition, the as-nanocomposite Ag/ZnO–TiO2 showed good degradation for different structure dyes including crystal violet, methylene blue and methyl orange under UV light irradiation. Furthermore, the product Ag/ZnO–TiO2 prepared by microwave-assisted method still has certain stability under ultraviolet light after three cycles experiment. According to the capture experimental results, we proposed the possible mechanism of the photodegradation about organic pollutants in the aqueous system.