Synthesis of (Ag,F)-modified anatase TiO2 nanosheets and their enhanced photocatalytic activity

Abstract

A series of TiO₂ nanosheets are prepared with different amounts of AgNO₃ and HF solution through a solvothermal process. The samples are characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), laser Raman spectroscopy (LRS), electron paramagnetic resonance (EPR), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). From the results it is clear that the added HF solution inhibits the crystallite size growth in the [001] direction, and induces the formation of the TiO₂ nanosheets with highly exposed (001) facets. There is a strong interaction between the Ag nanoparticles and the TiO₂ support. The (Ag,F)-modified TiO₂ catalyst exhibits high activity of MB photodegradation under both UV light and visible light irradiation. Two mechanisms of photocatalysis under UV light and visible light irradiation were discussed and proposed. It is indicated that the strong interaction between the Ag nanoparticles and the TiO₂ support improves the photocatalytic activity of TiO₂ nanosheets.