Study on preparation and visible-light activity of Ag–TiO₂ supported by artificial zeolite

The material of Ag–TiO₂ supported by artificial zeolite (Ag–TiO₂/Z) was synthesized by the sol–gel method. Tetrabutyl titanate was used as the precursor, AgNO₃ as the Ag source, and artificial zeolite as a carrier. The samples were analyzed by XRD, SEM, EDS, XPS, UV–Vis DRS and N₂ adsorption–desorption isotherms. The results indicated that Ag–TiO₂/Z had an anatase crystal phase, the dopant Ag was in the form of Ag⁰ and Ag₂O nanocrystalline, and the existence of Ag₂O can introduce impurity level and reduce the band gap of TiO₂, which can lead to the absorption spectrum of the sample shift into the region of visible light, with 2.75 eV band gap energy. In addition, the photocatalytic properties of the samples were investigated by the degradation of methylene blue (MB) under visible light irradiation. The degradation rate of 3 at% Ag–TiO₂/Z reached 93% within 90 min, which exhibited the best photocatalytic activity among all the samples. Meanwhile, with reused photocatalyst, the stability of 3 at% Ag–TiO₂/Z was evaluated by the degradation of MB, whose efficiency stayed at around 89% after 5 times degradation. This study will be conducive to the development of visible-light activity of TiO₂ and the application of aqueous pollutants.