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1.
Transparent conducting SnO2 powders doped with 10% Fe content were prepared by a polymerized complex method under acidic solutions, and annealed finally at 550 °C, and at 600 °C. These samples were characterized by X-ray diffraction, magnetization, and Mössbauer spectrometry at room temperature. Rutile SnO2 phase was obtained for both samples, and the crystallite sizes were in the range of 13-14 nm. Both samples exhibit magnetization and the saturation magnetization was smaller for the sample annealed at 600 °C than for sample annealed at 550 °C. Room temperature Mössbauer spectra for both samples showed the presence of two different paramagnetic iron sites but no magnetic sextets. These results suggest that ferromagnetism originates from magnetic defects and not directly from iron ions. 相似文献
2.
Guang-Rui Gu Ying-Ai LiYan-Chun Tao Zhi HeJun-Jie Li Hong YinWei-Qin Li Yong-Nian Zhao 《Vacuum》2003,71(4):487-490
Titanium dioxide (TiO2) films have been successfully deposited on metal alloy substrates by radio-frequency magnetron reactive sputtering in an Ar+O2 gas mixture. The effects of gas total pressure on the structure and phase transition of TiO2 films were studied by X-ray diffraction and Raman spectra. It is suggested that the film structure changes from rutile to anatase while work gas total pressure changes from 0.2 to 2 Pa. The structure of TiO2 films is not affected by the film thickness. 相似文献
3.
Choong-Soo ChiJinwook Choi Yongsoo JeongOh Yeon Lee Han-Jun Oh 《Thin solid films》2011,519(15):4676-4680
Micro-arc oxidation method is a useful process for mesoporous titanium dioxide films. In order to improve the photocatalytic activity of the TiO2 film, N-Eu co-doped titania catalyst was synthesized by micro-arc oxidation in the H2SO4/Eu(NO3)3 mixture solution.The specific surface area and the roughness of the anodic titania film fabricated in the H2SO4/Eu(NO3)3 electrolyte, were increased compared to that of the anodic TiO2 film prepared in H2SO4 solution. The absorbance response of N-Eu titania film shows a higher adsorption onset toward visible light region, and the incorporated N and Eu ions during anodization as a dopant in the anodic TiO2 film significantly enhanced the photocatalytic activity for dye degradation. After dye decomposition test for 3 h, dye removal rates for the anodic TiO2 film were 60.7% and 90.1% for the N-Eu doped titania film. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the surface enlargement and the new electronic state of the TiO2 band gap by N and Eu co-doping. 相似文献
4.
G. Socol Yu. Gnatyuk N. Smirnova C. Sutan A. Stanculescu I.N. Mihailescu 《Thin solid films》2010,518(16):4648-6387
We report on pulsed laser deposition of TiO2 films on glass substrates in oxygen, methane, nitrogen and mixture of oxygen and nitrogen atmosphere. The nitrogen incorporation into TiO2 lattice was successfully achieved, as demonstrated by optical absorption and XPS measurements. The absorption edge of the N-doped TiO2 films was red-shifted up to ∼ 480 nm from 360 nm in case of undoped ones.The photocatalytic activity of TiO2 films was investigated during toxic Cr(VI) ions photoreduction to Cr(III) state in aqueous media under irradiation with visible and UV light. Under visible light irradiation, TiO2 films deposited in nitrogen atmosphere showed the highest photocatalytic activity, whereas by UV light exposure the best results were obtained for the TiO2 structures deposited in pure methane and oxygen atmosphere. 相似文献
5.
Tae Ho Jun 《Materials Letters》2010,64(21):2287-2289
Cr-doped TiO2 thin films with different band gaps were prepared. Higher Cr doping was beneficial to the formation of the rutile-TiO2 phase over the anatase-TiO2 phase. A 4.8% Cr-doped thin film indicated a band gap of 2.95 eV, which was lower than the band gap of the rutile-TiO2. Cr doping was accompanied by the formation of not only the rutile-TiO2 phase but also the Cr2O3 phase, lead to the degradation of the hydrophilicity. The TiO2 thin films with the mixed phase were not desirable to improve the hydrophilicity. 相似文献
6.
Jorge Medina-Valtierra Claudio Frausto-ReyesMartín Ortiz-Morales 《Materials Letters》2012,66(1):172-175
Anatase (TiO2) thin films were obtained by immersion of glass plates into a titanium sol-gel precursor followed by calcination at 450 °C for 3 h. The Raman results for the CO2 laser irradiated TiO2 films show that laser radiation is able to promote favorable changes of anatase phase in anatase/rutile mixtures. Nevertheless, the transformation process level depends on laser characteristics and scan speed of the radiation treatment. 相似文献
7.
The effect of zirconium dioxide addition on crystal structure of sol-gel TiO2 mesoporous films and powders has been investigated by means of Raman spectroscopy, X-Ray diffraction, and Atomic force microscopy. Zirconium incorporation (up to 30 mol%) into TiO2 lattice resulted in the formation of Ti1 − xZrxO2 solid solution with anatase structure for the binary powders has been proved. Appearance of tetragonal ZrO2 phase was observed for the samples with high zirconium content. 相似文献
8.
Anatase nano-TiO2 thin films were fabricated by reactive magnetron sputtering metal Ti target followed by thermal annealing in air at 450 °C for 2 hrs. The crystalline structure of the sample films were characterized by X-ray diffraction (XRD) and the hydrophilicity was characterized with the diameters of 1 μl water drop. The films were irradiated by oxygen plasmas and the effects of the radio frequency (rf) power, the gas pressure and the irradiation time of the oxygen plasmas on the hydrophilicity of the TiO2 thin films were investigated. Hydrophilicity can be induced by oxygen plasmas and further more the hydrophilicity shows high stability whenever under the natural light or in dark. 相似文献
9.
Sol-gel SiO2/TiO2 and TiO2/SiO2 bi-layer films have been deposited from a polymeric SiO2 solution and either a polymeric TiO2 mother solution (MS) or a derived TiO2 crystalline suspension (CS). The chemical and structural properties of MS and CS bi-layer films heat-treated at 500 °C have been investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscospy. Water contact angle measurements show that MS SiO2/TiO2 and CS TiO2/SiO2 bi-layer films exhibit a natural superhydrophilicity, but cannot maintain a zero contact angle for a long time over film aging. In contrast, CS SiO2/TiO2 bi-layer films exhibit a natural, persistent, and regenerable superhydrophilicity without the need of UV light. Superhydrophilic properties of bi-layer films are discussed with respect to the nature of the TiO2 single-layer component and arrangement of the bi-layer structure, i.e. TiO2 underlayer or overlayer. 相似文献
10.
Photocatalytic properties of porous TiO2/Ag thin films 总被引:1,自引:0,他引:1
In this study, nanocrystalline TiO2/Ag composite thin films were prepared by a sol-gel spin-coating technique. By introducing polystyrene (PS) spheres into the precursor solution, porous TiO2/Ag thin films were prepared after calcination at a temperature of 500 °C for 4 h. Three different sizes (50, 200, and 400 nm) of PS spheres were used to prepare porous TiO2 films. The as-prepared TiO2 and TiO2/Ag thin films were characterized by X-ray diffractometry (XRD) and by scanning electron microscopy to reveal structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methylene blue under UV irradiation.When PS spheres of different sizes were introduced after calcination, the as-prepared TiO2 films exhibited different porous structures. XRD results showed that all TiO2/Ag films exhibited a major anatase phase. The photodegradation of porous TiO2 thin films prepared with 200 nm PS spheres and doped with 1 mol% Ag exhibited the best photocatalytic efficiency where ∼ 100% methylene blue was decomposed within 8 h under UV exposure. 相似文献
11.
Self-assembled and vertically aligned rutile titania nanorods and thin films with a preferred [002] axial orientation were grown on substrates of fluorine-doped tin dioxide, using a hydrothermal method. Each nanorod was made of a bundle of densely packed and ultra fine nano-fibers growing along the [002] direction. The results show that ethanol substitution of water as solvent is highly effective in promoting the one-dimensional growth of the rutile nanorods and increasing their packing density in the thin films, which offers a simple-but-effectual leverage to monitor the nanorod structures for varied applications. 相似文献
12.
The structural properties of Ge doped polycrystalline CuGaSe2 films with potential applications in solar cell device technology have been studied by Raman spectroscopy at 300 K and by Photoluminescence (PL) spectroscopy at 300 K and 2 K. The films were intentionally doped with max. 200 keV Ge ions using one- and three-stage ion implantation processes. The Raman spectra of as grown films are dominated by the A1-mode (breathing mode) of the CuGaSe2 absorber at 184 cm− 1. It was found, that in doped films the Raman mode intensities are reduced and the B2-modes (TO at 249 cm− 1 and LO at 273 cm− 1) take over. This implies an increase in structural disorder induced, probably, by bond reorientation effects that favor excitation of asymmetric lattice vibrations (B2) instead of the symmetric ones (A1). Moreover, it was found, that the Raman bands of doped films exhibit asymmetric broadening representative of a Fano line-shape. Changes were more pronounced in films doped at one-stage. The PL-emission of films subjected to one-stage process was enhanced, which supports an increase in structural disorder particularly for these films. On the contrary, for films doped in three-stages, the PL bands are less intensive and the Raman bands are less broadened. 相似文献
13.
R. Alexandrescu I. Morjan R. Birjega I. Soare I. Voicu F. Dumitrache E. Vasile 《Thin solid films》2007,515(24):8438-8445
Undoped and Fe-doped TiO2 nanopowders with Fe/Ti (atomic ratio) precursor concentration ranging from 7% up to 25% have been prepared by the IR laser pyrolysis technique. A sensitized mixture of TiCl4 and Fe (CO)5 was used as titanium and iron precursor, respectively. Reference undoped titania samples with a major concentration of anatase phase (about 90%) were obtained by the same technique by using very high flows of the oxidizing agent (air). The effects of the iron-dopant concentration on the essential structural properties of the resultant powders such as the phase formation, the crystallinity, the average particle size and distributions were systematically investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The decrease of the TiO2-anatase crystalline phase, the simultaneous increase of the amorphous phase and the decrease in size of particle mean diameter appear as main effects induced by the Fe-dopant concentration. 相似文献
14.
Jing Yang 《Thin solid films》2008,516(8):1736-1742
To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2 films were obtained by heating a TiO2 gel in an ionized N2 gas. The as-synthesized TiO2−x−yNxCy films have shown an improvement over titanium dioxide in optical absorption and photocatalytic activity such as photodegradation of methyl orange under visible light. The process of the oxygen atom substituted by nitrogen and carbon was discussed. Oxygen vacancy induced by the formation of Ti3+ species and nitrogen and carbon doped into substitution sites of TiO2 have been proven to be indispensable for the enhance of photocatalytic activity, as assessed by UV-Vis Spectroscopy and X-ray photoemission spectroscopy. 相似文献
15.
We have studied the structural and optical properties of thin films of TiO2, doped with 5% ZrO2 and deposited on glass substrate (by the sol-gel method). The dip-coated thin films have been examined at different annealing temperatures (350 to 450 °C) and for various layer thicknesses (63-286 nm). Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range of 1.62-2.29 and the porosity is in the range of 0.21-0.70. The coefficient of transmission varies from 50 to 90%. In the case of the powder of TiO2, doped with 5% ZrO2, and aged for 3 months in ambient temperature, we have noticed the formation of the anatase phase (tetragonal structure with 14.8 nm grains). However, the undoped TiO2 exhibits an amorphous phase. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 350 °C. The obtained structures are anatase and brookite. The calculated grain size, depending on the annealing temperature and the layer thickness, is in the range (8.58-20.56 nm). 相似文献
16.
A sol-gel dip coating technique was used to fabricate TiO2/SnO2 nano composite thin films on soda-lime glass. The solutions of SnO2 and TiO2 were mixed with different molar ratios of SnO2:TiO2 as 0, 3, 4, 6, 8, 9, 10.5, 13, 15, 19.5, 25 and 28 mol.% then the films were prepared by dip coating of the glasses. The effects of SnO2 concentration, number of coating cycles and annealing temperature on the hydrophilicity of films were studied using contact angle measurement. The films were characterized by means of scanning electron microscopy, X-ray diffraction and atomic force microscopy measurements. The nano composite thin films fabricated with 8 mol.% of SnO2, four dip coating cycles and annealing temperature of 500 °C showed super-hydrophilicity. 相似文献
17.
Václav Valeš Václav HolýMaja Buljan Vesna JanickiSigrid Bernstorff 《Thin solid films》2012,520(14):4800-4802
We report on structural, morphological and ordering properties of Fe2O3/TiO2 nanoparticles embedded in SiO2-based multilayers. We investigated the structure of these systems by X-ray diffraction and grazing incidence small angle X-ray scattering after post-growth annealing. We found that the presence of TiO2 promotes the growth and crystallization of the nanocrystals of Fe2O3. In multilayers containing both Fe2O3 and TiO2, crystalline nanoparticles create partially ordered three-dimensional arrays. 相似文献
18.
Investigation on solar photocatalytic activity of TiO2 loaded composite: TiO2/Eggshell, TiO2/Clamshell and TiO2/CaCO3 总被引:1,自引:0,他引:1
The TiO2/Eggshell, TiO2/Clamshell and TiO2/CaCO3 loaded composites were prepared by sol-gel method and characterized by XRD and SEM. Their photocatalytic activities were measured through the degradation of Acid Red B under solar light irradiation. The influences of TiO2 loaded content, heat-treated temperature and time on the photocatalytic activities were reviewed. The effects of irradiation time and dye initial concentration on the photocatalytic degradation were also investigated. The results showed that the photocatalytic activity can be greatly enhanced by appropriate TiO2 loaded content. 相似文献
19.
The nanocomposite oxide (0.2TiO2-0.8SnO2) doped with Cd2+ powder have been prepared and characterized by XRD and their gas-sensing sensitivity were characterized using gas sensing measurement. Experimental results show that, bicomponent nano anatase TiO2 and rutile SnO2 particulate thick film doped with Cd2+ behaves with good sensitivity to formaldehyde gas of 200 ppm in the air, and the optimum sensing temperature was reduced from 360 °C to 320 °C compared with the undoped Cd2+ thick film. The gas sensing thick films doped with Cd2+ also show good selectivity to formaldehyde among benzene, toluene, xylene and ammonia as disturbed gas and could be effectively used as an indoor formaldehyde sensor. 相似文献
20.
为了精确控制共沉淀包膜法制备掺杂TiO2粉体的反应条件,本文通过对Men+(Ni2+、La3+、Fe3+、Al3+)在NaHCO3-NH3.H2O体系中离子沉淀反应平衡的热力学分析,得到了Men+-CO32--NH3.H2O体系中不同总氨浓度cN和总碳浓度cC时各金属离子总浓度与pH值的关系图,并由此确定了金属离子完全沉淀的最佳pH值.热力学分析表明,以NaHCO3-NH3.H2O作为沉淀剂,采用共沉淀包膜法制备掺杂TiO2粉体时,当cN=0.010 mol/L和cC=1.000 mol/L时,反应的适宜沉淀pH为9.0左右. 相似文献