Ceramics-Silikáty 52, (4) 278 - 290 (2008)

Nanocrystalline titanium (IV) dioxide powders with particle size in the range 30 to 45 nm and surface area in the range from 150 to 600 m² /g were prepared by hydrothermal treatment of aqueous TiO₂.xH₂O suspension which was synthesized from aqueous solutions of TiOSO₄, TiOCl₂, TiCl₄ and TiCl₃ , respectively, by chemical reaction with 1M ammonium hydroxide. The structure of prepared samples was determined by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED). The morphology and microstucture characteristics were also obtained by scanning electron microscopy (SEM) and high resolution electron microscopy (HRTEM). The nitrogen adsorption-desorption was used for determination of surface area (BET) and porosity. The photocatalytic activity of the prepared titania samples were assessed by photocatalytic decomposition of Orange II dye in an aqueous slurry under UV irradiation at 365 nm wavelength. The best photocatalytic activity showed the samples of gel precursors prepared from TiCl₄ and TiCl₃. The result suggests that the photocatalytic activity on the decomposition of Orange II dye depends on the particle size of samples prepared by hydrothermal synthesis.