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采用浸渍-提拉法和溶胶-凝胶法制备TiO2/ACF复合光催化材料,用BET、XRD和SEM等进行表征。结果表明,溶胶-凝胶法制备的复合材料由于负载了大量TiO2,其比表面积明显低于浸渍法;浸渍法制备的复合材料随着粘结剂添加量的增加,比表面积呈减小趋势。溶胶-凝胶法制备的复合材料的表面TiO2锐钛晶型较明显,浸渍-提拉法无明显的锐钛晶型。采用浸渍-提拉法制备的TiO2/ACF复合材料,TiO2以粒状负载于ACF表面;溶胶-凝胶法中TiO2在ACF表面形成一层薄膜,由于焙烧,薄膜产生裂隙,暴露出ACF,有利于吸附和催化作用的同时进行。 相似文献
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溶胶-凝胶法制备纳米TiO2后处理的研究 总被引:2,自引:0,他引:2
采用溶胶-凝胶法制备锐钛型纳米TiO2,并用水热法等不同方法对其进行后处理。采用XRD、XPS和TEM对所得的TiO2粉体的晶型、粒径大小、表面组成进行了表征。研究了制备一定粒径的锐钛型纳米TiO2的后处理方法。 相似文献
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采用溶胶-凝胶法制备TiO2/活性炭(AC)光催化剂,采用XRD分析了纳米TiO2晶型,SEM观察了活性炭负载前后表面形貌.正交试验分析了各因素对光催化降解甲基橙的影响.结果表明:制备的纳米TiO2为纯锐钛矿型,催化剂以不规则碎片包覆在活性炭表面.复合材料在TiO2浓度0.441 mol/L,50℃烘干后,pH=3的环境下降解甲基橙,脱色率达到95.5%.溶液pH值是催化降解的主要影响因素. 相似文献
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MWCNT/TiO_2复合材料的制备、表征及光催化降解植物多酚的研究 总被引:2,自引:1,他引:1
以钛酸丁酯为前驱体,以表面改性后的多壁碳纳米管(MWCNT)为载体,采用溶胶-凝胶法制备出TiO2粒子负载在碳纳米管表面的复合光催化剂,通过XRD、TEM、IR、UV-vis等手段对复合材料进行了表征。结果表明,TiO2均匀包覆在碳纳米管的表面,经500℃煅烧2 h后,纳米TiO2以锐钛型为主,粒径约15 nm,复合材料在紫外区及可见光区对光都有优良的吸收性能。并研究了MWCNT/TiO2光催化剂在紫外灯照射下对单宁酸(模拟栲胶)光催化降解情况,以CODcr的变化评价溶液中栲胶的降解情况。结果表明,在光照6 h后,溶液CODcr值从初始的3 024降到2 000,而用纯TiO2要达到相同的效果需要20 h以上。说明复合材料对单宁酸有很好的光催化降解效果,对研究制革植鞣废水的处理提供了参考。 相似文献
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镍掺杂对二氧化钛光催化性能影响的研究 总被引:5,自引:0,他引:5
采用溶胶-凝胶法制备了纳米二氧化钛以及不同掺镍量的TiO2纳米粒子(原料中Ni∶TiO2的摩尔分数为1%、3%、5%、7%、9%)。用紫外光照射甲基橙溶液的光催化降解实验研究了掺镍对二氧化钛光催化剂催化效率的影响,试验结果表明,当用n(Ni)∶n(TiO2)=5%的Ni(NO3)2溶液进行镍掺杂时,制得的TiO2催化剂光催化效率最高,但与纯TiO2相比,镍掺杂会减弱TiO2的光催化效率。X射线衍射分析表明,未掺杂的TiO2以锐钛矿和金红石两种晶型混合存在,镍掺杂后TiO2的晶型几乎全为锐钛矿。镍掺杂后会减小TiO2粒子的尺寸,增大其比表面积。 相似文献
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Synthesizing and Comparing the Photocatalytic Properties of High Surface Area Rutile and Anatase Titania Nanoparticles 总被引:2,自引:0,他引:2
Rutile titania nanocrystalline particles with high specific surface areas were directly prepared by thermal hydrolysis of titanium tetrachloride aqueous solution. The as-prepared rutile titania powder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area analysis, and Fourier transform Raman and IR spectroscopies. Neither anatase nor amorphous titania could be detected in this titania powder by XRD, Raman spectroscopy, and high-resolution TEM. In the phenol degradation reaction, the rutile titania powder with an initial crystalline size of 7 nm was found to have higher photocatalytic activity than that of anatase titania with the same specific surface area. The rutile titania powders calcined at 300° and 450°C also showed a relatively high photocatalytic property. The high activity of the as-prepared rutile titania was attributed to the abundance of hydroxy groups in the powder, as was proven by thermogravimetric analysis data, which provided more active sites for the degradation reaction. 相似文献
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《Journal of the European Ceramic Society》2004,24(7):2125-2130
Titania–hydroxyapatite composites were prepared by soaking compacts of a powder mixture consisting of crystalline titania and calcium carbonate (vaterite) to form apatite in simulated body fluid (SBF). The apatite crystal formed on compacts in SBF at 37 °C within 2 days. The apatite-forming ability of the mixtures was much higher than that of titania crystals such as anatase or rutile on their own. Calcium carbonate (vaterite), which has high solubility in the aqueous solution, plays an important role in the apatite formation; the dissolution is suggested to increase the supersaturation of the apatite in SBF. Formation of titanium hydroxide groups, which may induce the apatite formation, is drastically promoted on the powder-compacts by the soaking in SBF, independently of the structures of the titania crystals (anatase or rutile). The apatite formation on the compact of the titania–calcium carbonate (vaterite) powder mixture containing the anatase phase occurs in a shorter period than that on the one of titania (rutile)–calcium carbonate (vaterite). Crystalline titania (anatase phase) is suggested to be particularly effective in inducing the apatite nucleation. 相似文献
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《Ceramics International》2017,43(4):3761-3768
Nanofibers of titania and composite nanofibers of titania and multiwall carbon nanotubes were synthesized by electrospinning using a sol-gel process combined with activated carbon nanotubes. The relationships of treatment temperature, carbon nanotube content on the crystal phase, fiber morphology, and electric properties are reported. It is found that the rutile phase becomes more prominent at low heat treatment temperatures with an increase of carbon content in nanofibers, be it for higher amount of carbon due to reducing atmosphere or due to an increase in MWCNT. Atmospheric control and lower heat treatment temperatures enable crystalline nanocomposite fibers of anatase where the level of rutile is below the detection limit of XRD or Raman spectroscopy. This work provides a new path to fabricate electrospun TiO2/MWCNT nanocomposite nanofibers with limited C-induced rutile phase. 相似文献
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溶胶-凝胶制备TiO2空气净化特性研究 总被引:1,自引:0,他引:1
利用XRD等手段对以钛酸四丁酯为原料采用溶胶-凝胶法制备的TiO2纳米粒子的表面特性及其对空气环境中乙醛的光催化降解性能进行了测定。结果表明,乙醇与钛酸四丁酯体积比、溶胶pH、加水量和焙烧温度等对催化剂降解乙醛的活性有显著影响。在实验条件范围内,较短胶凝时间制备出的纳米粉末晶粒尺寸较小,活性较高。焙烧温度不但影响TiO2粉末的粒径,而且对晶型的组成也有影响。锐钛矿晶型的光催化活性明显高于金红石晶型,锐钛矿型向金红石型转变的临界温度在(500~600) ℃。实验得到TiO2最佳制备条件为:V(乙醇)∶V(钛酸四丁酯)=4、溶胶pH=3.0、加水量4 mL和焙烧温度(400~500) ℃。 相似文献
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We report an in situ TEM investigation of the growth and transformation in nanometer-sized titania powders. The powders were produced through precipitation of titanium tetrachloride under different pH conditions. The initial phase of the produced powders was amorphous or was a mixture of anatase and brookite according to the pH conditions. During calcination, the anatase particles grew and transformed into rutile. The transformation temperature increased with increasing pH value. In situ TEM observations showed that the anatase particles were absorbed into rutile, and then rutile particles grew by coalescence. Furthermore, small pores were observed to form in samples prepared with high pH from the effects of hydroxyl ions and zeta potential. Pore formation increased the surface area, which delayed the transformation and nucleation of rutile. This explains the difference of growth and transformation of titania powders produced under different pH conditions during calcination. 相似文献
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不同晶型纳米二氧化钛的水热合成 总被引:2,自引:1,他引:1
水热法合成了不同晶型、形貌和大小的纳米二氧化钛。利用X射线衍射(XRD)和透射电镜(TEM)对所得的样品进行了表征。研究了pH值、水热反应温度和水热反应时间对纳米二氧化钛晶型、形貌和晶粒尺寸的影响。结果表明,前驱体pH值是决定产品晶型、晶粒尺寸和形貌的主要因素。随着水热反应温度的升高,纳米二氧化钛的晶粒尺寸逐渐变大,但pH=3.0时所形成的锐钛矿型纳米二氧化钛的晶粒尺寸却几乎不变;随着水热反应时间的延长,金红石型纳米二氧化钛晶粒的生长速度最快,而锐钛矿型的纳米二氧化钛的晶粒生长速度则最慢。 相似文献
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S. T. Aruna M. Muniprakash V. K. William Grips 《Journal of Applied Electrochemistry》2013,43(8):805-815
In this paper, the effect of titania particles preparation on the properties of Ni–TiO2 electrocomposite coatings has been addressed. Titania particles were prepared by precipitation method using titanium tetrachloride as the precursor. The titanyl hydroxide precipitate was subjected to two different calcinations temperatures (400 and 900 °C) to obtain anatase and rutile titania particles. These particles along with commercial anatase titania particles were separately dispersed in nickel sulfamate bath and electrodeposited under identical electroplating conditions to obtain composite coatings. The electrodeposited coatings were evaluated for their microhardness, wettability, corrosion resistance, and tribological behavior. The variation of microhardness with current density exhibited a similar trend for all the three composite coatings. The composite coating containing anatase titania particles exhibited higher microhardness and improved wear resistance. However, the corrosion resistance of the composite coating containing commercial titania powder was superior to that of plain nickel, Ni–TiO2 composite coatings containing anatase and rutile titania particles. The poor corrosion resistance of these composite coatings was attributed to the higher surface roughness of the coatings. This problem was alleviated by incorporating ball-milled titania powders. The composite coatings with higher surface roughness were modified with a low surface energy material like fluoroalkyl silane to impart hydrophobic and superhydrophobic properties to the coatings. Among these coatings, Ni–TiO2–9C coating exhibited the highest water contact angle of 157°. 相似文献
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采用溶胶-凝胶法在低温下制备出Fe3+掺杂TiO2(Fe3+/TiO2)溶胶,研究Fe3+掺杂对TiO2催化性能的影响,用TG/DTA技术分析TiO2粉末的热分解过程,用XRD、TEM等表征Fe3+掺杂对TiO2晶型、晶粒尺寸、晶粒形貌的影响,结果表明:Fe3+掺杂会对纳米TiO2晶粒的粒径及晶体形貌产生影响,抑制TiO2晶型由锐钛矿向金红石的转变。将亚甲基蓝作为目标污染物进行光催化降解试验,紫外-可见漫反射吸收光谱分析表明:经适量Fe3+掺杂后的TiO2溶胶光催化活性提高,当硝酸铁与钛酸丁酯的物质的量比为0.20%时,光催化活性最佳。 相似文献