Synthesis of nanocrystalline Ga–TiO2 powders by mild hydrothermal method and their visible light photoactivity

In this work, nano-sized gallium doped titanium dioxide (Ga–TiO2) powders with different dopant concentrations (0.1, 0.6 and 1.2 mol%) were synthesized by a mild hydrothermal method dwelling at 150 °C for 10 h without any post heat treatment. The synthesized samples were characterized by X-ray diffraction (XRD), Brunauer–Emment–Teller (BET) specific surface area, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–visible light diffuse-reflection spectra (DRS). The photocatalytic activities were evaluated via photocatalytic decolorization of methyl orange under 420–780 nm visible light irradiation. Due to the small particle size, large specific surface area, improved visible light response and enhanced separation of photo-excited carriers, Ga–TiO2 photocatalysts exhibit better photocatalytic activity than that of Degussa P25 or un-doped TiO2, which prepared under the same processing conditions. Among all the Ga doped TiO2 photocatalysts, 0.6 mol% Ga–TiO2 shows the best photo-decolorization efficiency reaching up to 82%.