纳米二氧化钛薄膜的制备及特性研究

纳米二氧化钛薄膜由于具有优良的光催化活性而受到人们的重视。采用阳极电沉积的方法在ITO基体上制备二氧化钛钠米薄膜。研究了阳极电流密度和沉积时间对纳米二氧化钛薄膜结构和附着力的影响，利用扫描电子显微技术和X射线衍射技术分析了二氧化钛薄膜的表面形貌和组织结构，探讨了其光催化活性和亲水性。结果表明，纳米二氧化钛薄膜是由纳米级的颗粒组成，颗粒间存在纳米级小孔，该薄膜对于波长为400－700nm的可见光是透明的，具有优良的光催化活性和亲水性。     

纳米二氧化钛薄膜制备方法研究进展

二氧化钛纳米晶薄膜优异的性能使其成为研究焦点,制备二氧化钛薄膜有着重要的现实意义。介绍了近年来国内外二氧化钛薄膜制备技术的研究进展,主要涉及高活性二氧化钛光催化薄膜的制备(制备方法包括溶胶-凝胶法、丝网印刷法、激光化学气相沉积法、水热结晶法、电泳法等),负载二氧化钛薄膜常用的载体,以及在环境保护等方面的应用研究现状,并指出以后的研究方向。     

Photocatalytic activity of undoped and sulfur-doped TiO2 films grown by MOCVD for water treatment under visible light

Titanium dioxide ceramic coatings have been used as catalysts in green technologies for water treatment. However, without the presence of a dopant, its photocatalytic activity is limited to the ultraviolet radiation region. The photocatalytic activity and the structural characteristics of undoped and sulfur-doped TiO₂ films grown at 400 °C by metallorganic chemical vapor deposition (MOCVD) were studied. The photocatalytic behavior of the films was evaluated by methyl orange dye degradation under visible light. The results suggested the substitution of Ti⁴⁺ cations by S⁶⁺ ions into TiO₂ structure of the doped samples. SO₄^2? groups were observed on the surface. S-TiO₂ film exhibited good photocatalytic activity under visible light irradiation, and the luminous intensity strongly influences the photocatalytic behavior of the S-TiO₂ films. The results supported the idea that the sulfur-doped TiO₂ films grown by MOCVD may be promising catalysts for water treatment under sunlight or visible light bulbs.     

镍、碳共掺杂纳米二氧化钛薄膜的制备与光催化性能研究

为了增强纳米二氧化钛薄膜在紫外光下光催化降解罗丹明B溶液的能力,分别采用磁控直流溅射与射频溅射的方法,使用二氧化钛靶材、镍靶材、碳靶材,分别制备了碳非金属掺杂、镍金属掺杂以及镍、碳共掺杂的纳米二氧化钛薄膜,并利用扫描电子显微镜（SEM）、X射线衍射仪（XRD）和紫外可见分光光度计（UV-Vis）进行表征。SEM结果表明,与纯二氧化钛薄膜相比镍、碳共掺杂纳米二氧化钛薄膜晶粒细化,比表面积增大,薄膜表面聚集体为不规则的多边形颗粒状,有利于增大与污染物的接触面积;XRD结果表明该薄膜的晶粒减小,加快了光生电子空穴对的分离;薄膜的吸收极限红移,禁带宽度减小。在紫外光照射下,镍、碳共掺杂纳米二氧化钛薄膜的光催化性能最优,1 h降解了29.54%的罗丹明B溶液。     

溶胶-凝胶法制备二氧化钛薄膜的研究进展

光催化净化空气是一项造福人类的绿色环保技术。TiO₂薄膜化是光催化技术实用化的关键。介绍了近几年来溶胶-凝胶法制备TiO₂薄膜光催化净化空气的研究进展,对溶胶-凝胶法制备TiO₂薄膜的各种影响因素进行了分析,并探讨了提高TiO₂薄膜光催化能力的途径及其相关的光催化反应系统。     

二氧化硫脲为硫源制备硫掺杂二氧化钛及其光催化活性

以钛酸四丁酯为TiO2的前驱物,二氧化硫脲为掺杂硫的源物质,采用溶胶-凝胶法制备了掺硫改性的TiO2光催化剂。采用XRD对制备的掺硫二氧化钛结构进行了表征,探讨了溶胶-凝胶制备工艺、硫掺杂量及催化剂煅烧温度对该催化剂光催化活性的影响。结果表明,掺硫改性的TiO2经600℃煅烧后光催化活性有了明显提高,且硫的掺杂有一个最佳值,即二氧化硫脲的掺杂质量百分数为4%。经掺硫改性后的TiO2在可见光区具备更强的光催化活性,在波长不低于400nm的可见光作用下,对亚甲基蓝的4 h降解率最高可达89.5%。     

非金属掺杂的第二代二氧化钛光催化剂研究进展

寻求廉价、环境友好并具有可见光光催化活性的第二代光催化剂将是光催化发展进一步走向实用化的关键。氮掺杂的TIO2是新发现的具有可见光光催化活性的复合光催化剂,非金属掺杂可以使复合物的复合禁带宽度小于TIO2的禁带宽度,从而使TIO2的吸收边向可见光移动。对TIO2的氮、碳、硫、卤素掺杂国内外研究现状进行了系统评述,分析了提高TIO2可见光活性的原因,指出非金属元素特别是氮元素的阴离子掺杂是在不降低紫外光催化活性的基础上实现可见光响应的较好方法。     

Ag@AgCl-TiO2-粉煤灰微珠复合光催化剂的制备及其可见光光催化性能

采用离子交换法在粉煤灰微珠(FMS)表面沉积Ag@AgCl纳米颗粒,制备Ag@AgCl-FMS复合基底,采用水解-沉淀工艺,以TiCl4为钛源在复合基底表面再包覆纳米TiO2薄膜,经500℃煅烧2 h后得到Ag@AgCl- FMS-TiO2复合光催化剂. 对材料微观形貌、晶体结构、可见光光催化性能进行了表征与测试. 结果表明,复合基底表面包覆的TiO2薄膜均匀完整. 500℃煅烧后的物相为90%锐钛矿型TiO2和10%金红石型TiO2. 复合催化剂料在Ag@AgCl等离子共振效应的作用下,表现出明显的可见光响应,经可见光照射80 min后对甲基橙的降解率达99%,5次重复使用对甲基橙的降解率保持在85%.     

A Novel Method for Preparing V-doped Titanium Dioxide Thin Film Photocatalysts with High Photocatalytic Activity Under Visible Light Irradiation

The liquid phase deposition (LPD) method was successfully used for preparing V-doped TiO₂ thin film photocatalysts. In this simple and easily-controlled process, V-doped anatase TiO₂ thin films were directly deposited on a soda lime glass substrate placed in an aqueous solution containing Ti- and V-fluoro complex ions, followed by annealing. The thin films were analyzed by XRD, XPS, UV-vis. V⁴⁺ ions were introduced into the lattice of TiO₂ through in-situ substituting Ti⁴⁺. The absorption edge of V-doped TiO₂ films shifted to visible light region. The highly efficient photocatalytic activity was verified by the decomposition of methylene blue under visible light irradiation.     

Nanoparticle Deposition from Liquid Flame Spray onto Moving Roll-to-Roll Paperboard Material

Nanostructured coatings have been prepared on a flexible, moving paperboard using deposition of ca. 40-nm-sized titanium dioxide nanoparticles generated by a liquid flame spray process, directly above the paperboard, to achieve improved functional properties for the material. Properties such as surface wettability can be extensively improved by a thin layer of nanoparticles on the substrate. Owing to the vulnerability to heat, the substrate needs to be moved rapidly through the flame. This, on the other hand, generates a setting for a roll-to-roll coating process, which favors upscaling of the method. In this article, we characterize the flame process for nanoparticle coating and quantify the operational window for this method. The amount of deposited material as a function of substrate speed through the flame is discussed. Although the thermophoretic flux of nanoparticles is estimated to be very high from the hot flame onto the cold substrate, other factors were observed to limit the deposited amount of particles. Total mass yields of 5%–20% of the injected precursor material into the titanium dioxide nanocoating on the paperboard were achieved. With these yields, a highly hydrophobic surface was obtained by a mass loading of 10–50 mg/m² of titanium dioxide on the paperboard.     

纳米TiO2薄膜制备方法的研究进展

纳米二氧化钛以其优异的化学、物理性能受到关注。薄膜是纳米二氧化钛的重要形式,制备纳米二氧化钛薄膜具有重要意义和很好的应用前景。依据制备工艺中温度的要求,对制备纳米二氧化钛薄膜的方法进行了概述,高温制备的工艺主要有溶胶-凝胶法、水热法、气相沉积法,低温制备工艺主要有电泳沉积法、紫外光照射法、电化学制备法、模板自组装制备法。     

Preparation of TiO2 thin films using octadecylamine Langmuir-Blodgett films and evaluation of their photocatalytic activity

A study was conducted to demonstrate that nanometer-thick titanium dioxide (TiO(2)) thin films could be prepared by the hydrolysis of titanium potassium oxalate using octadecylamine (ODA) Langmuir-Blodgett (LB) films as templates. The amount of TiO(2) generated in the LB film was found to be proportional to the number of deposited ODA layers, which enables precise control of the TiO(2) film thickness. After heat treatment of the LB films at 300-600°C, the photocatalytic activities of the resulting TiO(2) films were determined from the decomposition of stearic acid cast films when irradiated with UV light for different time periods. Higher photocatalytic activity was observed in TiO(2) films heat treated at lower temperatures.     

Growth of titanium dioxide nanopetals induced by single wall carbon nanohorns

A novel titanium dioxide architecture, called titanium dioxide nanopetals, was obtained through two sequential vapour techniques, metal-organic chemical vapour deposition (MOCVD) and magnetron sputtering on a single wall carbon nanohorn (SWCNH) bed, resulting in a surprising synergistic effect. The new composite material was characterized by scanning and transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The particular experimental conditions under which this unusual growth was obtained are discussed in detail. The photocatalytic degradation of phenol under UV light irradiation demonstrated that this novel material exhibited a significant increase of photoactivity in comparison with the titanium dioxide thin films deposited by RF magnetron sputtering and the SWCNHs coated with titanium dioxide by MOCVD.     

钨离子掺杂对钛片表面TiO2薄膜光催化活性的影响

采用溶胶-凝胶法制备了负载在钛片上掺杂W⁶⁺的TiO₂薄膜光催化剂。研究结果表明,焙烧温度为520 ℃,TiO₂薄膜光催化剂活性最好;W⁶⁺的掺杂提高了TiO₂薄膜的光催化活性。当W⁶⁺掺杂浓度为6.04×10¹⁶个·cm^-3时,W⁶⁺-TiO₂薄膜光催化剂光催化活性最高,XRD结果表明,掺杂W⁶⁺前后TiO₂均为锐钛矿相,并未检测出任何钨的氧化物。     

Preparation, Characterization, and Photocatalytic Activity of N, S-Codoped TiO2 Nanoparticles

The doping of titanium dioxide (TiO₂) with various metal or nonmetal elements has been considered as an effective strategy to extend the photoactive wavelength region to visible light. In this paper (nitrogen [N] and sulfur [S])-codoped anatase TiO₂ nanoparticles were prepared via a sol–gel route, followed by a heat treatment at elevated temperatures. The as-prepared samples were extensively characterized by X-ray diffraction, UV–Vis absorption spectroscopy, and X-ray photoelectron spectroscopy. The N, S-codoped TiO₂ nanoparticles showed a strong visible light absorption and exhibited an enhanced photocatalytic activity for the degradation of methylene blue as compared with the pure, N- or S-doped TiO₂ under either UV light or solar light irradiation.     

Selective area synthesis of aligned carbon nanofibers by laser-assisted catalytic chemical vapor deposition

Arrays of freestanding bamboo-type carbon nanofibers were grown on the surface of a porous alumina substrate by laser-assisted catalytic chemical vapor deposition. A continuous wave argon ion laser operated at a wavelength of 488 nm was used to thermally decompose pure ethylene over nickel catalysts. Two different catalyst preparation methods were used and are compared with respect to the synthesis of aligned nanofibers. First, a thin nickel film (50 nm) was evaporated on the substrate and was subsequently laser annealed into nanoparticles. This preparation produced non-aligned nanofiber films. Second, a 50 nm thick catalyst layer was electrochemically deposited within the pores of an alumina substrate. This preparation produced an array of vertically aligned nanofibers. A growth rate dependence on radial position within the irradiated area was observed. Average linear growth rates ranging from 554 nm/s to 25 μm/s are reported. The nanofibers were examined by scanning electron microscopy and Raman spectroscopy. Fiber texture and nanotexture were determined by lattice fringe analysis from high resolution transmission electron microscopy images. The alignment mechanism is also discussed.     

提高二氧化钛光催化性能的研究进展

对过渡金属离子掺杂、贵金属表面沉积、表面光敏化、表面超强酸化等几种提高TiO2 光催化剂活性的方法进行了综述 ;介绍了近年来为了提高TiO2 光催化过程的效率 ,而发展形成的微波场作用下光催化反应、热催化与光催化的耦合反应、室温等离子体光催化反应、生物光催化反应、电场助光催化反应等几种新型高效光催化反应技术的研究现状与进展 ;并对TiO2 光催化的应用进行了展望。     

Low-temperature fabrication of TiO<Subscript>2</Subscript> film on flexible substrate by atmospheric roll-to-roll CVD

Titanium dioxide (TiO₂) thin film was fabricated using titanium isopropoxide as a precursor through an atmospheric low-temperature roll-to-roll chemical vapor deposition method. TiO₂ was deposited on the PET substrate in the temperature range of room temperature to 100°C, and the working pressure was 740 Torr. The surface morphology of TiO₂ thin film was analyzed by field emission scanning electron microscopy and a 2D surface profiler. The results revealed that the growth rate of TiO₂ film was 31 nm/min at 100°C, and it also showed that the surface is uniform and smooth. Moreover, the lowest root mean square roughness (R _q) value of 1.87 nm was obtained for TiO₂ film prepared at 100°C. The composition of TiO₂ film was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The film showed very good chemical and optical properties while increasing the substrate deposition temperature. The UV–Vis spectroscopy analysis revealed that TiO₂ films exhibited excellent optical transmittance, more than 91% observed in the visible region.     

MOLECULAR STRUCTURE OF INTERFACES FORMED WITH PLASMA-POLYMERIZED SILICA-LIKE PRIMER FILMS: PART II. CHARACTERIZATION OF THE PRIMER/METAL INTERFACE USING X-RAY PHOTOELECTRON SPECTROSCOPY IN SITU

X-ray photoelectron spectroscopy (XPS) was performed in situ on plasma-polymerized silica-like films that were deposited onto metal substrates. Relatively thick films (∼8.0 nm) had spectra that were typical of bulk amorphous silicon dioxide (a-SiO 2 ). When thinner films were analyzed (∼2.4 nm), a Si(2p) peak emerged that was due to the formation of silicon suboxide at the interface. Changes in the metal and metal oxide peaks showed that oxidation of the substrates during plasma etching and deposition occurred. It was determined that during the initial stages of plasma deposition, metal atoms from the substrate migrated to the metal-oxide surface. This resulted in preferential oxidation of metal atoms with the formation of silicon suboxide at the film/metal interface. In addition, interfacial suboxide formation was shown to have a dependence upon the diffusivity of the metal substrate atoms through the surface oxide of the metal. As a result, more interfacial suboxide was observed to form for depositions on titanium substrates in comparison with depositions on aluminum substrates. A detailed analysis of the atomic species detected with in situ XPS enabled us to develop a model of the molecular structure at the a-SiO 2 /metal interface for plasma depositions on aluminum and titanium substrates. When the possible chemical reaction routes for film deposition were considered, the formation of primary Al-O-Si and Ti-O-Si bonds at the interface was proposed.     

Wood surface modification by in-situ sol-gel deposition of hybrid inorganic–organic thin films

Interest in the use of nanoparticles of iron, titanium, aluminum, and zinc oxides in transparent coatings for wood is increasing. Such nano-composite coatings have the potential of not only preserving the natural color of the wood, but also stabilizing the wood surface against the combined degradative effects of sunlight and moisture. The nanoparticles can be used as additives to coating formulations or deposited directly as thin films on a substrate. Thin film deposition can be accomplished by plasma-enhanced chemical vapor or by sol-gel deposition. This paper describes sol-gel deposition of a hybrid inorganic–organic thin film on wood using a mixture of metal–organic precursors and its effect on weathering properties of the wood surface. Presented at the 5th International Woodcoatings Congress: Enhancing Service Life, sponsored by the Paint Research Association (PRA), in Prague, Czech Republic, on October 17–18, 2006.