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本文采用溶胶 凝胶法制备二氧化钛纳米微粒。用XRD分析了二氧化钛胶体经不同温度热处理后的晶粒粒径。分析表明温度在 4 73K时TiO2 微粒呈锐钛矿结构 ,粒径约为 5 5nm。在 6 73K以上TiO2 粒径迅速增大 ,微粒出现锐钛相与金红石相混晶结构。 973K时TiO2 微粒完全转化为金红石相。用晶界结构弛豫的观点解释粒径随热处理温度变化关系 相似文献
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硫酸亚钛爆轰制备纳米TiO2粒子 总被引:2,自引:0,他引:2
以硫酸亚钛,氨水,硝酸铵和黑索金炸药为主要原料,结合沉淀法和爆轰技术对爆轰合成纳米二氧化钛进行了研究,同时利用X射线粉晶衍射仪(XRD)和高分辨透射电子显微镜(HRTEM)等对爆轰灰及经过在空气中500℃,1h处理后的爆轰灰进行测试分析,结果表明:收集的爆轰灰是以金红石和锐钛矿相的二氧化钛为主粒径为(30±10)nm的球形超微粉,同时含有少量的杂质(Ti7O13和C),经过500℃,1h的热处理除杂后,制备的二氧化钛纳米粉末仍为金红石和锐钛矿相组成的混晶,金红石相和锐钛矿相的相对含量比为9∶1,二氧化钛晶粒有轻微长大现象. 相似文献
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不同晶型纳米TiO2的溶剂热合成及其光催化活性研究 总被引:3,自引:0,他引:3
采用不同的醇溶剂,以六亚甲基四胺为沉淀剂,以TICl3为前驱体,通过溶剂热的方法控制合成出纳米级的锐钛矿型、金红石型和板钛矿型的二氧化钛.通过XRD、TEM、UV-Vis光谱和XPS能谱对其进行了表征,研究了醇的种类、六亚甲基四胺的量对二氧化钛相组成及光催化性能的影响.结果发现,以甲醇为溶剂,酸性条件有利于生成锐钛矿相,碱性条件有利于生成金红石相和板钛矿相.溶剂热条件下可以得到氮掺杂的TiO2-xNx.光催化降解甲基橙活性结果表明锐钛矿和板钛矿混晶具有最好的光催化活性. 相似文献
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为了研究双微乳液法在制备纳米级光催化剂的应用,以TiCl4和NH3.H2O为原料,采用十六烷基三甲基溴化铵-正丁醇-环己烷-水微乳体系制备Fe3+掺杂纳米TiO2,对粉末的晶体结构进行X射线衍射表征,并以其对p-甲酚的降解考察其光催化活性。结果表明,在较小的掺杂量时,Fe3+掺杂量的提高可以提高TiO2的光催化活性,进一步提高掺杂量将引起光催化活性的降低;掺杂Fe3+可导致纳米TiO2的粒径减小;Fe3+的半径较小以及Fe2O3的熔点较低均有利于TiO2从锐钛矿向金红石的相变;当Fe3+掺杂摩尔分数为0.06%,煅烧温度为550℃时,纳米TiO2的光催化活性最高,此时形成TiO2的锐钛矿和金红石相的混晶;乳液中含水量也会影响晶相的组成和粒径大小,随着含水量增加产物中出现了一定比例的金红石相。 相似文献
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混晶结构纳米TiO2粉的光催化活性 总被引:15,自引:0,他引:15
以钛酸四丁酯为钛源制备混晶结构纳米TiO2粉,研究了纳米TiO2的光催化活性与颗粒晶相结构之间的关系.结果表明,当金红石相的质量分数少于18.53%,光催化活性随着金红石相的增多而降低;当金红石相的质量分数为18.53%-28.2%时,随着金红石相的增多,光催化活性逐渐增强,在28.2%附近具有最高的光催化活性,与纯锐钛矿结构纳米TiO2粉的光催化活性相当;金红石相含量继续增加,则光催化活性逐渐降低.适量金红石相的存在有利于锐钛矿相中的电荷分离,使光催化活性提高. 相似文献
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TiO2纳米微粒的溶胶—凝胶法制备及XRD分析 总被引:22,自引:0,他引:22
本文采用溶胶-凝胶法制备二氧化钛纳米微粒。用XRD分析了二氧化钛胶体经不同温度热处理后的晶粒粒径。分析表明温度在437K时TiO2微粒呈锐钛矿结构,粒径约为5.5nm。在673K以上TiO2粒径迅速增大,微粒出现锐钛相与金红石相混昌结构。973K时TiO2微粒完全转化为金红石相。用晶界结构弛豫的观点解释粒径随热处理温度变化关系。 相似文献
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Ultraviolet-?and visible-light-responsive titania-based photocatalysts were synthesized and employed in the photocatalytic oxidation of NO(x). Sol-gel processes using tetrabutyl orthotitanate and ethanol under acid catalyzed condition and controlled calcination were performed to synthesize titanium dioxide with a mixed crystal lattice of anatase, brookite and rutile phases. The TiO(2) prepared under calcination at 200?°C exhibited high photocatalytic activity for degradation of NO(x) under both ultraviolet (UV) and visible-light illumination. The experimental results showed that up to 70% removal of NO(x) could be obtained in a continuous flow type reaction system under irradiation with visible light. The calcination temperature has an important influence on the particle size and lattice structure of TiO(2). It is also found that the peculiar mixed-phase structure of TiO(2), evidenced from Raman, x-ray diffractometry (XRD), and UV-vis spectroscopy, was inferred to be an important factor for visible-light absorption and NO(x) removal activity under a wide range of visible-light illumination. 相似文献
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Three mixed-phase TiO2 powders, containing ~80 volume % anatase and ~20 volume % rutile, were prepared from amorphous titanium hydroxide and three different salt matrices—pure sodium chloride, pure Na2CO3, and pure disodium hydrogen phosphate (DSP). Amorphous titanium hydroxide and salt mixtures were heat treated at 875°C in a rapid thermal annealing system for different times, according to the time–temperature phase transformation graphs. Time-dependent UV degradation of aqueous solutions of methylene blue dye (15 ppm) in the presence of mixed-phase powders was used to monitor the activity of the catalysts. Microstructural study of the powders by scanning electron microscope and transmission electron microscope combined with phase analysis by XRD and optical absorbance by UV-absorption spectroscopy indicated that the higher photocatalytic activity of the powder obtained from pure DSP salt could be explained by its smaller rutile particle size and anatase–rutile interparticle bonding. 相似文献
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Ce-TiO2光催化剂的制备与性能研究 总被引:1,自引:0,他引:1
采用溶胶-凝胶法制备了稀土Ce离子掺杂的纳米TiO2光催化剂(Ce-TiO2),通过XRD、FT-IR、UV-Vis、PL、Nano-sizer纳米粒度分析仪等对Ce-TiO2样品进行了表征和分析,并以亚甲基蓝(MB)作为目标降解物,考察了不同掺杂浓度及经不同温度热处理后的Ce-TiO2样品对MB的光催化降解效果,结果表明所制备样品的晶型均为锐钛矿相和金红石相的混晶相,Ce离子的掺杂拓展了TiO2在可见光区的光谱响应范围,提高了TiO2光催化活性。当pH值为1.5,Ce的掺杂量为n(Ce)∶n(TiO2)=1∶300,热处理温度为600℃条件下制备的样品其催化活性显著高于Degussa P25。 相似文献
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Laser ablation technique was adopted to prepare titania nanospheres; scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) were employed to characterize the morphology and structure of the product. The results demonstrate that TiO2 nanospheres with mixed-phase (rutile and anatase) structure were successfully fabricated by laser ablation of titanium target in water. We proposed that changed temperature and pressure after the laser ablation is responsible for the co-existence of the rutile phase and the anatase phase. The mixed-phase titania nanospheres (MTNSs) show superior photocatalytic properties compared with commercial titania powder, which is ascribed to the mixed-phase structure. 相似文献
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Water-soluble anatase, mixed-phase (anatase and rutile) and rutile TiO2 nanoparticles (NPs) or nanorods were synthesized under mild solution conditions using polyethylene glycol 400 (PEG 400) as a stabilizer and HCl as a phase controlling reagent. The photocatalytic properties of these NPs with different crystal phases were evaluated by photocatalytic degradation experiments of methyl orange (MO). As-prepared pure anatase TiO2 NPs show a higher photocatalytic activity than other samples and commercial P25, which may be related to the high crystallinity, the pure anatase phase, small size and the enhanced absorbability associated with the existence of PEG 400 on the NP surface. 相似文献