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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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锐钛矿型TiO2纳米粉体的电化学沉淀法制备及其表征 总被引:1,自引:0,他引:1
利用阴离子交换膜为隔膜将电解槽分为两室,控制阴极室电极的恒定电流密度,在电解过程中消耗阴极室溶液中的H+浓度,促使TiO2+与电解产生的OH-中和水解反应,形成TiO2.xH2O均匀沉淀,在不同温度的热处理后,得到不同晶型的纳米TiO2微粒.TEM和XRD分析表明在773K焙烧2h后,TiO2微粒呈锐钛矿型结构,粒径约为30~50nm;在873K热处理后可得到金红石相约占3.85%的锐钛矿型和金红石型混晶结构的TiO2粉体.本文对其形成的机理进行了初步的探讨. 相似文献
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热处理对溶胶-凝胶TiO2薄膜的晶相转变和性能影响 总被引:13,自引:1,他引:12
以钛酸丁酯(TPOT)为有机醇盐前驱体,采用溶胶-凝胶技术制备了TiO2溶胶。为测量方便起见,分别制备了凝胶粉体和薄膜,并对样品进行了不同温度的热处理。X射线衍射(XRD)、椭偏仪和紫外-可见光谱(UV-vis)的测量表明:随热处理温度的升高,TiO2的结构由非晶到锐钛矿再到金红石相转变,400℃为锐钛矿相,600℃开始出现金红石相,800℃完全转变为金红石相;晶粒尺寸随热处理温度的升高而逐渐增大,锐钛矿结构的晶粒尺寸范围是2.5-5.5nm,金红石结构的晶粒尺寸范围是5.9-6.8nm;TiO2薄膜的折射率随热处理温度的升高而增大,同时薄膜厚度降低;禁带宽度随热处理温度的升高而增大,同时薄膜厚度降低;禁带宽度随热处理温度升高而变窄,锐钛矿结构的禁带宽度为3.45eV,而金红石结构的禁带宽度为3.30eV。 相似文献
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研究了浸渍预处理前后TiN纳米粉体的气-固相反应,分析了浸渍液对TiN纳米粉体择优生成金红石相TiO2的作用。结果表明,在氧化温度为350~550℃时,TiN纳米粉体直接氧化生成以锐钛矿相为主的TiO2,而经过盐酸-正丁醇混合液浸渍预处理后,在380℃空气中,TiN纳米粉体氧化生成以金红石相为主的TiO2,XRD和TEM分析表明可以得到粒径16 nm的棒状金红石相TiO2纳米粉体。盐酸是TiN纳米粉体低温择优氧化生成金红石相TiO2的根本原因,而正丁醇主要起抑制产物纳米TiO2的团聚作用。 相似文献
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Optimized method for preparation of TiO2 nanoparticles dispersion for biological study 总被引:1,自引:0,他引:1
The objective of the present study was to develop a practical method to prepare a stable dispersion of TiO2 nanoparticles for biological studies. To address this matter a variety of different approaches for suspension of nanoparticles were conducted. TiO2 (rutile/anatase) dispersions were prepared in distilled water following by treated with different ultrasound energies and various dispersion stabilizers (1.0% carboxymethyl cellulose, 0.5% hydroxypropyl methyl cellulose K4M, 100% fetal bovine serum, and 2.5% bovine serum albumin). The average size of dispersed TiO2 (rutile/anatase) nanoparticles was measured by dynamic light scattering device. Agglomerate sizes of TiO2 in distilled water and 100% FBS were estimated using TEM analysis. Sedimentation rate of TiO2 (rutile/anatase) nanoparticles in dispersion was monitored by optical absorbance detection. In vitro cytotoxicity of various stabilizers in 16-HBE cells was measured using MTT assay. The optimized process for preparation of TiO2 (rutile/anatase) nanoparticles dispersion was first to vibrate the nanoparticles by vortex and disperse particles by ultrasonic vibration in distilled water, then to add dispersion stabilizers to the dispersion, and finally to sonicate the nanoparticles in dispersion. TiO2 (rutile/anatase) nanoparticles were disaggregated sufficiently with an ultrasound energy of 33 W for 10 min. The formation of TiO2 (rutile/anatase) agglomerates in distilled water was decreased obviously by addition of 1.0% CMC, 0.5% HPMC K4M, 100% FBS and 2.5% BSA. For the benefit of cell growth, FBS is the most suitable stabilizer for preparation of TiO2 (rutile/anatase) particle dispersions and subsequent investigation of the in vivo and in vitro behavior of TiO2 (rutile/anatase) nanoparticles. This method is practicable to prepare a stable dispersion of TiO2 (rutile/anatase) nanoparticles for at least 120 h. 相似文献
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Stoichiometric TiO2 nanoparticles (1-5 nm) were prepared by reactive-layer-assisted deposition (RLAD), in which Ti was initially deposited on a multilayer of H2O (or NO2) on a Au(111) substrate at approximately 90 K. The composition and atom-resolved structure of the nanoparticles were studied by XPS and STM. The approximately 5 nm TiO2 particles had either a rutile or anatase phase with various crystal facets. STS of the nanoparticles suggests size-dependent electronic structure. These well-defined nanoparticles can be used in molecular-level studies of the reactions and mechanisms of photocatalytic processes on TiO2 nanoparticle surfaces. 相似文献
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二氧化钛纳米晶的制备及光催化活性研究 总被引:5,自引:0,他引:5
本文用溶胶—凝胶法制备了不同晶相的TiO2纳米晶,将其负载于镍网上,以苯酚的降解为模型反应,研究对比了不同晶相TiO2纳米晶的光催化活性。结果表明,纯锐钛矿相的TiO2纳米晶的降解能力要强于锐钛矿与金红石混合相的TiO2纳米晶。 相似文献
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纳米TiO2粉晶的XRD研究 总被引:36,自引:5,他引:31
用溶胶-凝胶法制备了纳米TiO2粉晶,对不同温度自理的系列粉末用X射线衍射进行了研究,发现所得粉晶随热处理温度的不同发生了从锐钛矿到金红石相的转变。对系列粉晶进行了X射线衍射点阵参量计算,结合所得的晶粒度和微结构参数,发现纳米TiO2粉晶组元中存在着晶格畸变。 相似文献
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以钛酸丁酯为前驱物,无水乙醇为溶剂,采用溶胶-凝胶法制备了TiO2粉体,并采用紫外分光光度计、XRD等表征手段对TiO2的粒度、晶型结构进行了表征,分析了煅烧温度、TiO2晶型比例、溶液初始pH值等因素对TiO2结构性能及光催化活性的影响.结果表明:TiO2的锐钛矿晶型与金红石晶型的转相温度为700 ℃左右;采用溶胶-凝胶法制备TiO2时,控制溶液的pH值为4,煅烧温度为600 ℃,所得产物晶型全部为锐钛矿;当无水乙醇与钛酸丁酯的体积比为10:1时,产物的粒径为617 nm;且当配制溶液pH值为4,煅烧温度为600℃条件下,煅烧时间为40~60 min时,所制备TiO2的光催化效果较好,降解率较高;当光催化体系的pH值为9、以质量浓度为10 mg/L的亚甲基兰溶液浸泡2 h,TiO2的用量为0.25 g/L时,产物的降解率高达95.3%. 相似文献
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Nanostructured TiO2 is a most promising functional ceramic owing to its potential utilization in photocatalytical, optical and electrical applications. Nanostructured TiO2 coating was deposited through thermal spraying with liquid feedstock. Two types of crystalline structures were present in the synthesized TiO2 coating including anatase phase and rutile phase.The effect of spray flame conditions on the crystalline structure was investigated in order to control the crystalline structure of the coating. The results showed that spray distance, flame power and precursor concentration in the liquid feedstock significantly influenced phase constitutions and grain size in the coating. Anatase phase was formed at spray distance from 150 to 250mm, while rutile phase was evidently observed in the coating deposited at 100 mm. The results suggested that anatase phase was firstly formed in the coating, and rutile phase resulted from the transformation of the deposited anatase phase. The phase transformation from anatase to rutile occurred through the annealing effect of spraying flame. The control of the phase formation can be realized through flame condition and spray distance. 相似文献
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利用脉冲供氧反应磁控溅射制备了TiO2薄膜。分别用XRD和SEM研究了晶体结构和表面形貌。结果表明,当氧浓度高或Toff小,样品为锐钛矿结构,晶粒大小20~30nm;而当氧浓度低或Toff大,样品为金红石结构,晶粒大小10~15nm。应变分析表明,锐钛矿结构只存在压应变,大小0.044~0.211;而金红石存在压应变(大小0.021-0.398)或张应变(大小0.182~0.438)。氧浓度低(或Toff大)样品具有更平整的表面和更均一的晶粒大小。 相似文献
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Fiber-like TiO(2) nanomaterials were designed and created, for the first time, by in situ synthesis of TiO(2) nanoparticles in regenerated cellulose fibers in the wet state, followed by calcination at 400-800 °C to remove the cellulose matrix. The cellulose fibers were prepared in an NaOH/urea aqueous system with cooling via an industrial machine. The structure and properties of the fiber-like TiO(2) nanomaterials were characterized with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and photocatalytic degradation tests. The results revealed that the mean diameter of the fiber-like TiO(2) nanomaterials, which consisted of TiO(2) nanoparticles with a mean size from 21 to 37 nm, was 7-8 μm. The TiO(2) nanomaterials exhibited different crystallinity phases from anatase to rutile, depending on the calcinating temperature. With a decrease in the calcinating temperature from 800 to 400 °C, the surface area of the TiO(2) nanomaterials increased. The photocatalytic activity for the degradation of methyl orange of the anatase T-400 fibers calcined at 400 °C was the highest, compared with that at 600 and 800 °C. This work provided a simple and "green" pathway for the preparation of inorganic nanomaterials with different crystal structures by using porous regenerated cellulose matrix. 相似文献
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Co-doped TiO2 nanoparticles containing 0.0085, 0.017, 0.0255, 0.034, and 0.085 mol % Co(III) ion dopant were synthesized via sol-gel and dip-coating techniques. The effects of metal ion doping on the transformation of anatase to the rutile phase have been investigated. Several analytical tools, such as X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDAX) were used to investigate the nanoparticle structure, size distribution, and composition. Results obtained revealed that the rutile to anatase concentration ratio increases with increase of the cobalt dopant concentration and annealing temperature. The typical composition of Co-doped TiO2 was Ti(1-x)Co(x)O2, where x values ranged from 0.0085 to 0.085. The activation energy for the phase transformation from anatase to rutile was measured to be 229, 222, 211, and 195 kJ/mole for 0.0085, 0.017, 0.0255, and 0.034 mol % Co in TiO2, respectively. 相似文献