No abstract available

[en] A channeling study of TiOsub(x) crystals with different oxygen concentration has been performed. The results of planar channeling experiments show that the steering power of the pure oxygen planes appears to be weak to maintain a steered trajectory. The flux-peaking effect decreases with increasing O₂ concentration and is destroyed at a high interstial concentration (O/Ti>1). The axial channeling experiments show a weak flux-peaking effect for the lowest oxygen concentration (10 at%) while at higher concentrations the angular dip of oxygen sublattice is observed

[en] Published in summary form only

[en] Highlights: • TiO₂/G with CTAB has been enhanced dispersibility and conductivity in result. • The TiO₂/G with 7 wt% G and 30 wt% CTAB had the better conductivity in result. • CTAB only has an auxiliary role, not affects the crystalline structure of TiO₂/G. • TiO₂/G exists electron conductive paths for improving its conductivity.

[en] The sandwich-type polyoxometalate-based TiO₂ nanofibres were prepared successfully by electrospinning combining with chemical reaction and employed in ultra-deep desulfurization. OTA–CoVW–TiO₂ nanofibres (OTA = CH₃(CH₂)₁₇(CH₃)₃N, CoVW = [Co₄(H₂O)₂(VW₉O₃₄)₂]¹⁰⁻) confirmed the excellent desulfurization performance in extraction catalytic oxidative desulfurization system (ECODS). At 323 K, the 500 ppm DBT (dibenzothiophene) model oil was entirely removed within 20 min using 0.010 g 45 wt% OTA–CoVW–TiO₂ nanofibres as catalyst when O/S molar ratio was 4:1 and the dosage of model oil was 5 mL. The catalysts could be recycled and reused at least five times without remarkable decrease in catalytic activity. The desulfurization efficiencies for different substrates were shown as following order: DBT > 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) > BT (benzothiophene). Moreover, the possible mechanism was also elucidated.

[en] A novel, facile, catalyst-free, and low temperature process for the synthesis of discrete anatase TiO₂ nanocrystals has been developed in the absence of stabilizing agent. The product was shown to be discrete anatase TiO₂ nanocrystals with a mean diameter of 4.97 ± 0.9 nm and a specific surface area of 393 m²/g. By varying the water content and precursor concentration, the particle size could be tuned. Also, the resultant colloid solution was quite stable even in the absence of stabilizing agent because of the coverage of EG molecules on the particle surface. In addition, the anatase TiO₂ nanocrystals obtained in this work had highly thermal stability even at temperatures up to 800 ^oC. Also, as compared to Degussa P25 TiO₂ powders, they exhibited stronger absorption at 200-350 nm and higher transmittance in the visible light region. Thus, the new approach proposed in this work was practicable for the synthesis of anatase TiO₂ nanocrystals, particularly for those requested to have highly thermal stability and UVC-cut capability.

[en] When atomic layer deposition (ALD) is performed on a porous material by using an organometallic precursor, minimum exposure time of the precursor for complete coverage becomes much longer since the ALD is limited by Knudsen diffusion in the pores. In the previous report by Min et al. (Ref. 23), shrinking core model (SCM) was proposed to predict the minimum exposure time of diethylzinc for ZnO ALD on a porous cylindrical alumina monolith. According to the SCM, the minimum exposure time of the precursor is influenced by volumetric density of adsorption sites, effective diffusion coefficient, precursor concentration in gas phase and size of the porous monolith. Here we modify the SCM in order to consider undesirable adsorption of byproduct molecules. TiO₂ ALD was performed on the cylindrical alumina monolith by using titanium tetrachloride (TiCl₄) and water. We observed that the byproduct (i. e., HCl) of TiO₂ ALD can chemically adsorb on adsorption sites, unlike the behavior of the byproduct (i. e., ethane) of ZnO ALD. Consequently, the minimum exposure time of TiCl₄ (∼16 min) was significantly much shorter than that (∼71 min) of DEZ. The predicted minimum exposure time by the modified SCM well agrees with the observed time. In addition, the modified SCM gives an effective diffusion coefficient of TiCl₄ of ∼1.78 Χ 10^-2 cm²/s in the porous alumina monolith

No abstract available

[en] The electrochemical properties of n-type TiOsub(2-x) clectrode have been investigated in an aqueous 1M NaOH. The values of αnsub(a) from polarogram have been found to be 0.446-0.554. The diffusion coefficient of nsub(2) in 1M NaOH solution which is needed for the computation of reaction rate parameters mentioned above, has been measured by means of polarogram with DME. It has been to be 2.54x10sup(-5)cmsup(2)/sec at 25degC. Flatband potential and donor concentration by the Mott-Schottky plot have been estimated to be -0.63--1.50 V vs SCE and 2.07x10sup(19) -3.27x10sup(21)cmsup(-3), respectively. (author)

[en] TiO₂ and N-substituted TiO_2-xN_x were synthesized by using precipitation method. TiO_2-xN_x compound absorbed whole UV light as well as long wavelength of visible light (400 - 700 nm) because of the change of band gap from 3.2 eV to 1.77 eV. Results obtained revealed that TiO_2-xN_x showed higher activity than pure TiO₂ or P-25 for visible-photocatalytic degradation of 1,4-dichlorobenzene