Photocatalytic Properties of Mesoporous TiO2 Prepared by Hydrothermal Method

Mesoporous TiO2 was synthesized by hydrothermal treatment of titanic acid hydrate (H2Ti2O5 center dot xH(2)O) from potassium titanate (K2Ti2O5) via ion-exchange and glucose in aqueous solution at 220 degrees C, followed by a posttreatment in the presence of air at 520 degrees C. The photocatalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N-2 adsorption, and transmission electron microscopy (TEM). Results indicated that the prepared mesoporous TiO2 photocatalyst was micron-sized rod or needle morphology and had a mesoporous structure with a surface area of 106 m(2).g(-1), pore volume of 0.31 cm(3).g(-1), and a pore diameter of 8.06 nm. The crystal size was 12.3 nm. After calcination it was still anatase phase. The produced carbon considerably increased the thermal stability of the mesoporous TiO2 framework and inhibited undesirable grain growth as well as phase transformation during the hydrothermal and thermal treatment process. Photocatalytic degradation performance was investigated using methyl orange pollutant. The mesoporous TiO2 photocatalyst and Degussa P25 showed similar degradation behavior toward methyl orange. The mesoporous TiO2 could be recycled many times and this was because of the large grain size. Using KI as a probe reaction, we found that the photocatalytic mechanism of mesoporous TiO2 depended on photoinduced hole oxidation.