Solvothermal preparation of Ag/TiO2 nanoparticles and their photocatalytic activity

Abstract

Visible-light photoactive Ag/TiO2 catalysts were successfully prepared by a solvothermal method. The samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherm(BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-visible (UV-Vis) spectroscopy. The photodegradation of methylene blue (MB) solution was used to evaluate the photocatalytic activity of the catalyst under UV and visible light irradiation (λ > 400 nm). XRD results showed that the TiO2 was in the pure anatase phase. Ag nanoparticles were loaded onto the TiO2 nanoparticle surface and this had little influence on the crystal phase and the particle size of TiO2. The specific surface area of the samples was far higher than that for the samples prepared by the sol-gel method and the sample with Ag molar fraction of 5% had the highest value of 151.44 m2.g-1. The absorption spectrum of the Ag-modified TiO2 increased greatly and the adsorption edge was extended into the visible region. The photodegradation of MB solution followed a pseudo-first-order kinetic expression. The photocatalytic activities of the Ag/TiO2 composites prepared by the solvothermal method were remarkably higher than those prepared by the sol-gel method. Under UV or visible light irradiation, the optimal photoactivity was obtained for the sample with a Ag molar fraction of 5%. © Editorial office of Acta Physico-Chimica Sinica.