241 resultados para POLYCRYSTALLINE TIO2
Resumo:
The organic films of vanadyl-phthalocyanine (VOPc) compounds showed weak epitaxy growth (WEG) behavior on thin ordered para-sexiphenyl (p-6P) layer with high substrate temperature. The WEG of VOPc molecules standing up on the p-6P layer leaded to high in-plane orientation and their layer-by-layer growth behavior. In consequence, high quality VOPc films were obtained, which were consisted of lamellar crystals. Organic field-effect transistors with VOPc/p-6P films as active layers realized high mobility of above 1 cm(2)/V s. This result indicated that nonplanar compounds can obtain a device performance better than planar compounds, therefore, it may provide a rule to find disklike organic semiconductor materials.
Resumo:
一种TiO↓[2]可见光光催化剂的制备方法是将钛醇盐和乙醇反应得到透明液体之后,将该液体滴加到去离子水中,形成白色悬浊液后用无机酸调节pH值,经过超声处理,在80~160℃反应5~20小时,得到TiO↓[2]纳米晶溶胶;将溴化胺按溴化胺滴加到TiO↓[2]纳米晶溶胶中,滴加完毕继续回流反应5~10小时,然后减压蒸发溶剂,得到干凝胶,以乙醇为溶剂对干凝胶抽提萃取,在100~120℃下干燥,得到TiO↓[2]可见光光催化剂。本发明具有操作简单、反应条件温和、设备成本低、较强的可见光吸收和良好的可见光光催化性能等优点。
Resumo:
一种高折射率纳米晶TiO↓[2]溶胶-凝胶薄膜制备的方法,钛醇盐先进行快速水解,然后用无机酸胶溶,在溶胶-凝胶过程中形成晶相TiO↓[2]纳米颗粒,从而显著提高目标光学薄膜的折射率。本发明具有操作简单、反应条件温和、大面积无规则镀制、设备成本低和光学薄膜折射率高的优点。
Resumo:
一种用于费托合成重质烃的Co/TiO↓[2]催化剂重量百分比组成为:Co8-15wt%载体85-92wt%所述载体为重量比是ZrO↓[2]∶TiO↓[2]=0-10∶100的物质。提供了控制载体晶相的方法、制备了具有成本低、高性能的费托合成催化剂。
Resumo:
Many efforts have been made in fabricating three-dimensional (3D) ordered zinc oxide (ZnO) nanostructures due to their growing applications in separations, sensors, catalysis, bioscience, and photonics. Here, we developed a new synthetic route to 3D ZnO-based hollow microspheres by a facile solution-based method through a water-soluble biopolymer (sodium alginate) assisted assembly from ZnO nanorods. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy. Raman and photoluminescence spectra of the ZnO-based hollow microspheres were obtained at room temperature to investigate their optical properties. The hollow microspheres exhibit exciting emission features with a wide band covering nearly all the visible region. The calculated CIE (Commission Internationale d'Eclairage) coordinates are 0.24 and 0.31, which fall at the edge of the white region (the 1931 CIE diagram). A possible growth mechanism of the 3D ZnO superstructures based on typical biopolymer-crystal interactions in aqueous solution is tentatively proposed, which might be really interesting because of the participation of the biopolymer.
Resumo:
The poisonous intermediate of methanol oxidation on a Pt electrode was validated to be COad by electrochemical method. An approximate treatment to bimolecular elementary reactions on an electrode was advanced and then was applied to the stripping normal pulse voltammetry (NPV) for complex multistep multielectron transfer processes on plane electrodes to study the kinetics of completely irreversible process Of COad oxidation to CO2. The kinetic parameters for this process, such as standard rate constant (0) and anodic transfer coefficient (alpha) for this irreversible heterogeneous electron-transfer process at electrode/solution interface and apparent diffusion coefficient (D-app) for charge-transfer process within the monolayer of COad on electrode surface, were obtained with stripping NPV method. The effect of the approximate treatment on the kinetic parameters was also analyzed.
Resumo:
一种CeO↓[2]-TiO↓[2]复合氧化物载体,其特征在于Ce∶Ti(摩尔比)为0.05-0.4∶1,粒径为1-100nm,比表面积为50-250m↑[2]·g↑[-1],孔体积为0.3-1.2cm↑[3]·g↑[-1],采用一般的混合沉淀、抽滤、洗涤、干燥、焙烧可制成不同比例的水凝胶、醇凝胶、气凝胶CeO↓[2]-TiO↓[2]复合氧化物载体,其特征在于采用钛的无机物为原料,所以大大降低了成本。
Resumo:
TiO2 nanocrystallites were prepared front precursors tetra-n-butyl titanate (Ti(OC4H9)(4)) and titanium tetrachloride (TiCl4). The precursors were hydrolyzed by gaseous water in autoclave, and then calcined at predetermined testing temperatures. The samples were characterized by X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectra (FT-IR), and UV-vis diffuse reflectance spectra (DRS). The photocatalytic activities of the samples were evaluated by the photobleaching of methylene blue (MB) in aqueous solution and the photocatalytic oxidation of propylene in gas phase at ambient temperature. The results showed that the anatase phase nanocrystalline TiO2 could be obtained at relatively low temperatures (for precursor Ti(OC4H9)4 at I I VC and for TiCl4 at 140 degrees C, respectively), and that the as prepared samples exhibited high photocatalytic activities to photobleach MB in aqueous solution. As the calcination temperatures increasing. the decolor ratio of MB increased and reached the maximum value of nearly 100% at 600 degrees C, and then decreased. The photobleaching of MB by all samples followed the pseudo-first-order kinetics with respect to MB concentration.
Resumo:
Silver underpotential deposition (UPD)-induced surface atomic rearrangement of polycrystalline gold nanofilms was probed with use of surface plasmon resonance spectroscopy (SPRs) as a novel probe tool in combination with cyclic voltammetry. Interestingly, upon repetitive electrochemical UPD and stripping of Ag, the surface structure of the resulting bare Au film is rearranged due to strong adatom-substrate interactions, which causes a large angle shift of SPR R-theta curves, in a good linear relationship with the number of UPDs, to a lower SPR angle. The n, K values of the surfacial Au monolayers before and after the repetitive Ag UPD and stripping for 27 times are found to be 0.133, 3.60 and 0.565, 9.39, respectively, corresponding to the huge shift of 1.61degrees to the left of the SPR minima. Cyclic voltammetry experiments in 0.10 M H2SO4 are carried out before and after the UPD treatment to examine the quality of the whole electrode surface and confirmed this change. To correlate the angle change in SPRs with the profile change in the cyclic voltammogram, the UPD treatment was also performed on a Au(111) textured thin film. It was therefore confirmed that the resonance position of the SPR spectrum is very sensitive to the surface crystallographic orientation of the bare Au substrates. Some surface atomic rearrangement can cause a pronounced SPR angle shift.
Resumo:
中国科学院山西煤炭化学研究所