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TiO2 Nanocrystals (tio2 + nanocrystal)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Comparative Sol,Hydro(Solvo)thermal Synthesis of TiO2 Nanocrystals

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2006
Xianfeng Yang
Abstract Three small inorganic compounds [acetic acid (CH3COOH), nitric acid (HNO3), and hydrochloric acid (HCl)] andfive small organic compounds [n -butyl alcohol (CH3CH2CH2CH2OH), 1,2-propanediol (CH2OHCHOHCH3), propane-1,3-dicarboxylic acid (HOOCCH2COOH), butane-1,4-dicarboxylic acid (HOOCCH2CH2COOH), and ethylenediamine (H2NCH2CH2NH2)] with different donors (Cl,, NO3,, OH, COO,, and NH2) are used respectively and comparatively in different reaction media for tailoring the sol,hydrothermal synthesis of TiO2 nanocrystals at a specific reaction temperature and/or for different reaction times. Both anatase and rutile with a variety of nanostructures such as nanocubes, nanorods, nanoneedles, and their self-assembled nanospheres are selectively grown. Well-defined and crystalline anatase nanocrystals with a narrow size distribution are prepared in the presence of n -butyl alcohol. With the use of HCl, nanoneedles and their assembled nanospheres of phase-pure rutile are obtained under much less drastic conditions, even at 100 °C and for only two hours. The effects of the reaction media, synthesis temperatures, and aging times on the structures and shapes of the products are investigated in detail by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Facile Synthesis and Characterization of Luminescent TiO2 Nanocrystals,

ADVANCED MATERIALS, Issue 16 2005
D. Pan
A simple, two-phase approach using an autoclave is taken to synthesize high-quality anatase TiO2 nanocrystals with a narrow size distribution (see Figure). The size-tunable luminescence of the TiO2 nanocrystals is dominated by band-edge luminescence at room temperature. The nanocrystals could be readily dispersed in toluene after capping with stearic or oleic acid. [source]

Ordered Mesoporous Thin Films of Rutile TiO2 Nanocrystals Mixed with Amorphous Ta2O5

CHEMPHYSCHEM, Issue 5 2008
Jin-Ming Wu Dr.
Abstract Ordered mesoporous thin films of composites of rutile TiO2 nanocrystals with amorphous Ta2O5 are fabricated by evaporation-induced self-assembly followed by subsequent heat treatment beyond 780,°C. Incorporation of selected amounts of Ta2O5 (20 mol,%) in the mesoporous TiO2 film, together with the unique mesoporous structure itself, increased the onset of crystallization temperature which is high enough to ensure the crystallization of amorphous titania to rutile. The ordered mesoporous structure benefits from a block-copolymer template, which stabilizes the mesostructure of the amorphous mixed oxides before crystallization. The surface and in-depth composition analysis by X-ray photoelectron spectroscopy suggests a homogeneous intermixing of the two oxides in the thin film. A detailed X-ray absorption fine structure measurement on the composite film containing 20 mol,% Ta2O5 and heated to 800,°C confirms the amorphous nature of the Ta2O5 phase. Photocatalytic activity evaluation suggests that the rutile nanocrystals in the synthesized ordered mesoporous thin film possess good ability to assist the photodegradation of rhodamine B in water under illumination by UV light. [source]