Štengl, V.; Bakardjieva, S.; Murafa, N.; Houskova, V.; Lang, K., Visible-light photocatalytic activity of TiO2/ZnS nanocomposites prepared by homogeneous hydrolysis. Microporous and Mesoporous Materials 2008, 110 (2-3), 370-378.

Abstract: Photocatalytic active TiO2/ZnS composites were prepared by homogeneous hydrolysis of mixture of titanium oxo-sulphate and zinc sulphate in aqueous solutions with thioacetamide. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission microscopy (HRTEM) and electron diffraction (ED). The nitrogen adsorption–desorption was used for surface area (BET) and porosity determination. Diffuse reflectance UV/VIS spectra for evaluation of photophysical properties were recorded in the diffuse reflectance mode (R100) and transformed to an absorption spectra through the Kubelka–Munk function. The method of UV/VIS diffuse reflectance spectroscopy was employed to estimate band-gap energies of the prepared TiO2/ZnS nanocomposites. The photoactivity of the prepared TiO2/ZnS nanocomposites was assessed by the photocatalytic decomposition of Orange II dye in an aqueous slurry under irradiation of 255 nm, 365 nm and 400 nm wavelength. Under the same conditions, the photocatalytic activity of the commercially available photocatalyst (Degussa P25), the pure anatase TiO2 and sphalerite ZnS were also examined. The composite sample having the highest catalytic activity was obtained by hydrolysis of mixture solutions 0.63 M TiOSO4 and 0.08 M ZnSO4 · 7H2O. Link

Štengl, V.; Houšková, V.; Bakardjieva, S.; Murafa, N.; Havlín, V., Optically Transparent Titanium Dioxide Particles Incorporated in Poly(hydroxyethyl methacrylate) Thin Layers. Journal of Physical Chemistry C 2008, 112 (50), 19979-19985

Abstract: The optically transparent particles of titanium dioxide (rutile modification) were prepared by hydrolysis of aqueous solution of titanium(III) chloride in the presence of hydroxyethyl methacrylate. The transparent TiO2 doped with Ag or Pd nanoparticles was incorporated in a poly(hydroxyethyl methacrylate) thin layer and deposited on a quartz surface. The transparent particles of titania were characterized by measurement of particle size distribution, high-resolution transmission electron microscopy and selected area electron diffraction. Photocatalytic activity of prepared thin layers was determined by mineralization of Orange II dye, salicylic acid, butane, and acetone under UV radiation. The effects of the Ag and Pd doping on the morphology and microstructure of transparent TiO2 nanoparticles and their impacts on the photocatalytic activity were also studied. The photoactivity of the prepared transparent titania nanoparticles incorporated in thin poly(hydroxyethyl methacrylate) layers was assessed by the photocatalytic decomposition during irradiation at 365 or 254 nm. Link

Štengl, V.; Bakardjieva, S.; Murafa, N.; Opluštil, F., Zirconium Doped Titania: Destruction of Warfare Agents and Photocatalytic Degradation of Orange 2 Dye. The Open Process Chemistry Journal 2008, 1, 1-7.

Abstract: The homogeneous hydrolysis mixture of titanium oxo-sulphate and zirconium oxo-sulphate with urea at temperature 100°C has been used to prepare Zr4+ doped anatase with high specific surface area. The structure of the prepared samples was determined by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED). The morphology and microstructure characteristics were also obtained by scanning electron microscopy (SEM) and high resolution electron microscopy (HRTEM). The nitrogen adsorption-desorption was used for surface area (BET) and porosity determination. These oxides were taken for experimental evaluation of their reactivity with yperite (2,2´-dichloroethyl sulfide or HD or sulphur mustard), soman (3,3-dimethyl-2-butyl methylphosphonofluoridate or GD) and matter VX (O-ethyl S-2-(diisopropylamino)ethyl methylphosphonothionate). The photoactivity of the prepared samples was assessed by the photocatalytic decomposition of Orange 2 dye in an aqueous slurry under irradiation of 254 nm and 365 nm wavelength. Link

Houšková, V.; Štengl, V.; Bakardjieva, S.; Murafa, N., Photoactive materials prepared by homogeneous hydrolysis with thioacetamide: Part 2 - TiO2/ZnO nanocomposites. Journal of Physics and Chemistry of Solids 2008, 69 (7), 1623-1631.

Abstract: Photocatalytic active titanium dioxide (TiO2)/zinc oxide (ZnO) composite was prepared by homogeneous hydrolysis of a mixture of titanium oxo-sulphate and zinc sulphate in aqueous solutions with thioacetamide and subsequent annealing at the temperature of 600 °C. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission microscopy (HRTEM). Nitrogen adsorption–desorption was used for surface area (Brunauer–Emmett–Teller—BET) and porosity determination. The photoactivity of the prepared TiO2/ZnO samples was assessed by the photocatalytic decomposition of Orange II dye in an aqueous slurry under irradiation of 254 and 365 nm wavelengths. Under the same conditions, the photocatalytic activity of a commercially available photocatalyst (Degussa P25), the pure anatase TiO2 nanoparticles and cubic ZnO were examined. Link

Štengl, V.; Bakardjieva, S.; Murafa, N.; Houšková, V., Hydrothermal synthesis of titania powders and their photocatalytic properties. Ceramics-Silikaty 2008, 52 (4), 278-290.

Abstract: 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. Link

Bakardjieva, S.; Štengl, V.; Šubrt, J., Modeling of periodic ordered nanostructures: Shape-evolution and shape-control during precipitation of inorganic precursors and urea. Microscopy and Microanalysis 2008, 14 (Supplement S2), 358-359