Search results for "Titan"
showing 10 items of 1109 documents
One-Dimensional TiO2-B Crystals Synthesised by Hydrothermal Process and Their Antibacterial Behaviour on Escherichia coli
2016
We have successfully synthesised one-dimensional single crystals of monoclinic phase titanium dioxide nanostructures (TiO2-B), prepared by a hydrothermal process. Morphological characterization was carried out by atomic force and scanning and transmission electron microscopy techniques. In order to study the crystalline structure, samples were calcined at 500°C in an air-filled chamber. X-ray diffraction results indicated that as-prepared samples presented diffraction patterns of hydrate hydrogen titanate and those calcined at 500°C exhibited the TiO2-B and anatase phases, confirmed by Raman spectroscopy. Scanning electron microscopy results showed that the one-dimensional nanostructures ha…
Preparation of Photocatalytic Nanostructured TiO<sub>2</sub> Thin Films
2008
Photoactive films consisting of pure anatase, brookite or rutile were deposited on glass slides by a dip coating process from water dispersions or solutions obtained by using TiCl4 as the precursor. The films were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy. The photocatalytic activity of the various samples was evaluated by using the photooxidation of 2-propanol in gas solid regime as probe reaction. Brookite and anatase films showed a good photoactivity degrading the substrate and the propanone produced during the reaction.
A comparative study of the photocatalytic activities of iron-titanium (IV) oxide photocatalysts prepared by various methods; spray pyrolysis, impregn…
1995
Abstract A series of iron/titanium oxide photocatalysts of varying Fe 3+ content have beenprepared by a number of different methods and subjected to controlled thermal treatment. Specimens have been characterised in terms of their crystalline structure and morphology, and indicate solid solutions containing both the anatase and rutile phases of TiO 2 , together with the formation of pseudo-brookite in some specimens. Intrinsic photo-activity measurements have been performed using a standard liquid-phase photocatalytic reaction. Results indicate that the photocatalytic activity of the specimens differs according to the method of preparation, and that all solids containing iron (III) species …
Preparation, Characterization, and Photoactivity of Polycrystalline Nanostructured TiO2 Catalysts.
2004
Various preparations of nanostructured TiO2 starting from Ti(iso-OC3H7)4 or TiCl4 are reported. The samples were characterized by X-ray diffractometry, specific surface area and porosity determinations, scanning and transmission electron microscopy, and diffuse reflectance spectroscopy. 4-Nitrophenol photodegradation in aqueous medium was employed as a probe reaction to test the photoactivity of the catalysts. The photoactivity of some samples derived from Ti(iso-OC3H7)4 was found comparable with that of commercial powders. Calcination after the hydrolysis process was necessary to achieve crystallization of the particles before using them as photocatalysts for the reaction studied. The samp…
Preparation and characterisation of TiO2 (anatase) supported on TiO2 (rutile) catalysts employed for 4-nitrophenol photodegradation in aqueous medium…
1999
Abstract In this paper the preparation of two sets of polycrystalline photocatalysts prepared by supporting TiO2 (anatase) on TiO2 (rutile) or Al2O3 is reported. The powders were prepared by a wet impregnation method using titanium(IV) isopropylate. The impregnation was followed by thermal treatment and this procedure was repeated several times in order to obtain samples with progressively increasing amounts of TiO2 (anatase). The photocatalytic activity of all of the specimens was tested by carrying out the 4-nitrophenol photodegradation, used as a “probe” reaction, in aqueous medium and in different kinds of batch photoreactors. The solids were characterised by X-ray diffraction (XRD), sp…
Cr- and Sb-containing TiO 2 inorganic orange nano-pigments prepared by a relative long hydrocarbon chain polyol
2016
Abstract We report the preparation of a series of orange Cr- and Sb-containing TiO 2 nano-pigments by the polyol via using triethylenglycol (TEG). Poorly crystallized anatase nanopowders with nominal stoichiometric compositions Cr x Sb x Ti 1−2x O 2 , with 0 ≤ x ≤ 0.2, were obtained by heating at 180 °C a solution of antimony acetate, chromium acetylacetone and titanium butoxide in TEG. The transition temperature of the chromium- and antimonium-containing anatase nanoparticles into the rutile crystalline form occurred over the range of temperature between 500 and 650 °C, depending on the dopant amount. After annealing at 800 °C for short time the series of samples displaying the rutile stru…
Combined Adsorption/Photocatalytic dye removal by copper-titania-fly ash composite
2020
Abstract Achieving both photocatalytic efficiency and adsorption capacity is essential to produce a highly efficient photocatalyst. This study fabricated a new photocatalyst by combining copper (Cu) doped titanium dioxide (TiO2) with fly ash (FA). The photocatalysts were synthesized using mild acid (acid-FA/Cu/TiO2), base (base-FA/Cu/TiO2), and deionized water (rFA/Cu/TiO2) activated FA. EDX confirmed the inclusion of Cu in both Cu/TiO2 and FA/Cu/TiO2 composites. XRD analysis indicated the presence of the anatase form of TiO2 after Cu doping and incorporation into modified FA. All three FA/Cu/TiO2 composites demonstrated high absorption (UV and visible region) compared to their TiO2 and Cu/…
Effect of titanium dioxide crystalline structure on the photocatalytic production of hydrogen
2011
The effect of the crystalline phase of TiO 2 (anatase, rutile and brookite) on its photocatalytic activity in hydrogen production from methanol-water vapours has been investigated by testing a series of both home-made and commercial TiO 2 photocatalysts, either bare or surface-modified by deposition of a fixed amount, i.e. 1 wt%, of platinum as co-catalyst. For all of the TiO 2 samples the rate of hydrogen production increased by one order of magnitude upon Pt deposition, because of the ability of Pt to enhance the separation of photoproduced electron-hole pairs. Under irradiation in the 350-450 nm wavelength range, brookite and anatase showed similar photoactivities, both superior to that …
Nanostructured Pt–TiO2 composite thin films obtained by direct liquid injection metal organic chemical vapor deposition: Control of chemical state by…
2015
Abstract Nanostructured Pt–TiO 2 composite thin films were synthesized by direct liquid injection metal organic chemical vapor deposition process, using trimethyl(methylcyclopentadienyl)platinum and titanium isopropoxide as precursors. Surface and cross-sectional morphologies obtained by scanning electron microscopy and transmission electron microscopy evidenced the uniform distribution of platinum nanoparticles in the TiO 2 matrix. At higher Pt content, the X-ray diffraction analysis showed that the face-centered cubic phase of platinum appeared together with an anatase TiO 2 structure. In addition, as far as the platinum chemical state is concerned, the co-deposition of TiO 2 and Pt allow…
Anatase nanoparticles boundaries resulting from titanium tetrachloride hydrolysis
2017
An important factor that governs solar energy transformation into electrical or chemical energy, when using nanoparticles-based devices, is the spatial location of traps limiting electron transport. Evidences have been presented indicating that the electron diffusion is strongly influenced by nanoparticle boundaries, whose characteristics depend on the particles preparation. In the present work we have studied the role of hydrated excess proton structures in the formation of anatase nanoparticles boundaries in samples prepared by TiCl4 hydrolysis at low temperature and strong acidic conditions. The samples, constituted by anatase nanocrystals but, mainly, by amorphous titania, are studied b…