纳米TiO2的制备及其应用

综述了纳米TiO2的制备方法并比较了其优劣。介绍了纳米TiO2在光催化剂、环保、化妆品、吸波材料等领域的应用状况。指出了纳米TiO2制备过程中需要解决的问题。     

纳米TiO2光催化材料的制备及研究进展

纳米TiO2是一种无毒、反应速度快、降解效率高、无二次污染新型光催化剂，目前广泛应用于处理和降解废水、空气中有机污染物环境治理方面。本文首先全面介绍了制备TiO2光催化剂先进成熟技术方法。其次详细论述了光催化剂的改性、可见光敏化及新型光催化反应器的研究的提高三个方面，最后深入探讨了TiO2材料目前尚存在的问题以及展望TiO2作为光触媒的应用发展。     

纳米二氧化钛光催化剂的研究进展

纳米TiO2作为光催化剂在废水废气净化、抗菌环保等领域有着广泛的应用。本文简要介绍了纳米TiO2的结构、光催化机理、制备、改性以及应用，并展望了其今后的发展方向。     

天然矿物负载纳米TiO2研究进展

介绍了负载纳米TiO2光催化剂所用的矿物载体以及负载方法的研究进展，评述了各载体的特点，并展望了负载型光催化剂的研究发展方向。     

双通TiO2纳米管阵列光催化膜的研制

采用阳极氧化法,在钛箔上制备TiO2纳米管阵列,并利用HF气体去处其阻挡层,并作了SEM,Uv-Vis表征,表明获得了具有光催化性能的双通TiO2纳米管阵列.以双通TiO2纳米管阵列为光催化剂,在紫外光照射下进行甲基橙的降解实验,2 h内甲基橙降解率可以达到86%(A=484 nm),发现其光催化降解甲基橙的效果明显较好.     

纳米TiO2光催化技术与室内空气净化

纳米二氧化钛光催化剂在紫外光照射下,能将绝大多数污染物彻底氧化分解,且不产生二次污染.结合国内外纳米TiO2光催化技术的研究动态,分析了该技术在室内空气净化的广阔发展前景.     

Fe^3＋／Ce^3＋掺杂纳米TiO2的制备及光催化性能研究

采用溶胶-凝胶法制备了不同粒径的纯纳米TiO2和掺杂Fe^3＋和Ce^3＋的纳米TiO2。样品的X射线衍射（XRD）和透射电镜（TEM）表征说明：在相同的制备条件下，掺杂可以减小粒子粒径，掺Fe^3＋和Ce^3＋可以抑制晶相转变。光催化降解NO2的结果表明，在相同的制备方法和掺杂量的条件下合成的光催化剂对亚硝酸盐的降解率由高到低的顺序为：掺铁TiO2〉掺铈TiO2〉TiO2。     

可见光活性的Ru掺杂TiO2光催化剂的制备及光解水制氢性能研究

采用溶胶—凝胶法制备了系列Ru掺杂TiO2光催化剂,并利用XRD和UV-Vis漫反射光谱对样品进行了表征。结果表明:Ru掺杂阻止了TiO2纳米粒子由锐钛矿向金红石相的转变,提高了TiO2对可见光的吸收强度。Ru掺杂的最佳浓度为0.014%,在可见光的照射下,Ru(0.014%)/TiO2对光解水制氢有较高的活性。     

钇掺杂TiO2/膨润土纳米复合光催化剂的性能研究

以膨润土为载体,钛酸四丁酯和氯化钇为原料,采用溶胶-凝胶法制备钇掺杂TiO2/膨润土纳米复合光催化剂,运用X射线衍射(XRD)、差热-热重(DTA-TG)和红外光谱(IR)对纳米复合光催化剂进行了表征,在太阳光照射下,通过染料酸性红B的降解反应,考察其光催化活性。实验结果表明:钇掺杂TiO2已进入膨润土层间,经500℃热处理后,在膨润土表面有锐钛矿型TiO2生成,并结合牢固;适量的钇掺杂降低了TiO2粒子的粒径,显著提高了光催化降解有机物的活性;随着光照时间的延长,染料酸性红B的特征峰510nm强度逐渐减弱,2h后彻底消失,酸性红B的去除率达97.38%。     

卤族元素掺杂改性TiO_2光催化剂研究进展

廉价、环境友好、高稳定性并具有可见光光催化活性的光催化剂将是光催化发展进一步走向实用化的关键。卤素掺杂TiO2是具有可见光光催化活性的光催化剂,经卤素掺杂可以使TiO2的禁带宽度减小,从而使TiO2的吸收边红移。对TiO2的氟、氯、溴、碘掺杂的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,指出经卤族元素掺杂,TiO2在保持紫外区光催化活性的前提下,大大增加了其可见光响应能力,且有益于具有光催化活性晶相TiO2的形成。     

TiO2／活性炭的制备与光催化性能

以活性炭(AC)为载体，采用Sol-Gel法制备纳米TiO2／AC复合催化剂，利用SEM，TG-DTA，XRD等对其组成、结构、尺寸等进行分析和表征；并用紫外灯为光源，通过可溶性罗丹明B的光催化降解反映对其光催化活性进行研究。结果表明，TiO2纳米粒子的尺寸范围在30nm～60nm之间，其中TiO2的晶型主要为锐钛矿；活性炭载体与TiO2结合牢固，TiO2纳米颗粒不发生二维粘结；TiO2／AC复合体的比表面积比活性炭载体的大，对罗丹明B在200min内达到完全降解，而P25需要5h，TiO2／AC复合体具有很强的光催化活性，并且制备的TiO2／AC复合体催化剂容易从溶液中分离。     

Preparation of Nano-TiO2 Doped with Cerium and Its Photocatalytic Activity

Cerium-doped titanium dioxide nano-powders were prepared through the sol-gel method and the compound sampies were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and UV/Vis diffuse reflectance spectra （DRS）. The photocatalytic activity was evaluated by photocatalytic degradation of phenol in water. The results of XRD, TEM, and DRS show that pure TiO2 and Ce-doped TiO2 powder crystallines are a mixture of anatase and rutile ; the doping can retard the development of the grain size of TiO2 and decrease the diameter of TiO2 from more than 20 nm of pure TiO2 to about 10 nm; the doped TiO2 can improve the light absorption of TiO2 and suitable doping content tends to move the DRS spectrum of TiO2 towards visible light, but too much doping is not good for the light absorption ability. The results of the photocatalytic experiments show that doping with Ce content of 0.08% -0.4% can increase the photocatalytic activity of TiO2; however, doping with Ce content of 0.5% -2.5% can significantly decrease the photocatalytic activity of TiO2. The favorite doping content is 0.4% in the range of our experiments.     

真空冷喷涂技术制备塑料染料敏化太阳能电池中TiO_2散射层及其性能表征

塑料染料敏化太阳能电池(DSC)由于其质量轻、形状灵活可变、适用于低成本的连续式生产而成为一种很有发展前景的光化学太阳能电池。为了提高电池的效率,在室温下用真空冷喷涂技术将亚微米级制备在TiO2纳米晶体层表面形成一层光散射层。通过研究光散射层的影响以及散射层与纳米晶TiO2层的结合以理解电池效率提高的原因。为了对比,使用乙醇中添加亚微米级Al2O3或TiO2颗粒形成的悬浮液,采用溅射沉积法,制备出两种散射层。结果显示,所有三种散射层对光的反射能力均强于TiO2纳米晶体层。无照电流结果表明NC+VCSTiO2电池的散射层与TiO2纳米晶体层连接比另外两对组合更有效。因此,由吸附在散射层粒子表面的分子所决定的光诱导电子可以有效转移到TiO2纳米晶体层,并最终输出到外电流回路。假设由于散射效应电池效率提升13%,那么散射层与TiO2纳米晶体层层之间的良好结合贡献10%,最终导致使用NC+VCS-TiO2散射层的塑料染料敏化太阳能电池效率提升~23%。此外,NC+VCS-TiO2散射层的抗弯性能优于NC+SD-TiO2和NC+SD-Al2O3电池。     

Induction of sister chromatid exchanges and micronuclei by titanium dioxide in Chinese hamster ovary-K1 cells

Titanium dioxide (TiO2) has color properties of extreme whiteness and brightness, is relatively inexpensive, and is extensively used as a white pigment in a variety of materials. TiO2, an effective blocker of ultraviolet light, is frequently added to sunscreens and cosmetic creams. However, the genotoxicity of TiO2 remains to be controversial. In this report, we have demonstrated that TiO2 can be transported into Chinese hamster ovary-K1 (CHO-K1) cells. The effects of TiO2 on induction of sister chromatid exchanges (SCE) and micronuclei (MN) were then studied in these cells. The SCE frequency in CHO-K1 cells treated with TiO2 at a nonlethal dose range (0 to 5 microM) for 24 h was significantly and dose-dependently increased. By the conventional MN assay, TiO2 at the dose ranged from 0 to 20 microM slightly increased the MN frequency in CHO-K1 cells. However, in the cytokinesis-block MN assay, the number of MN per 1000 binucleated cells was significantly and dose-dependently enhanced in CHO-K1 cells treated TiO2 at the same dose range for 24 h. These results suggest that TiO2 is a potential genotoxic agent.     

纳米TiO2改性彩色涂层钢板的涂层老化性能

 采用超声预分散结合湿球磨法和分散剂复配方式对纳米TiO2进行表面改性处理,研制了均匀稳定分散的纳米TiO2分散液,表征了纳米TiO2改性后的彩涂板涂料及涂层性能。结果表明：纳米TiO2在分散液中的粒径集中分布在60~100 nm范围,可完全吸收330 nm左右的紫外线,对长波紫外线的散射吸收作用强于对短波紫外线的散射吸收。纳米TiO2改性彩涂板涂料用量为w(TiO2)=20%~30%。纳米TiO2改性处理可提高涂层柔韧性和附着力,减少涂层色差变化,降低失光率。涂层抗紫外老化性能优于同类传统彩涂板涂料涂层。     

溶胶 - 凝胶法制备 TiO2 及其冷喷涂性能研究

冷喷涂陶瓷涂层的现有研究表明, 大部分商业陶瓷粉末不适合用于冷喷涂, 而实验室制备的纳米团聚粉末 更易于冷喷涂。 溶胶 - 凝胶法是制备纳米 TiO2 最常用的方法之一, 具有工艺简单、 重复性高、 反应易控制等优点, 而且可以通过实验参数的改变从分子水平对反应进行控制, 从而获得结构形态各异的纳米粒子。 本文采用基于钛 酸四正丁酯水解反应的溶胶-凝胶法制备纳米锐钛矿TiO2, 研究粉末的微观结构并考察其冷喷涂性能, 在此基础上, 分析原料粉末性能对其冷喷涂性能的影响。 研究结果表明, 与商业 TiO2 粉末相比, 溶胶 - 凝胶法制备的 TiO2 粉 末具有良好的冷喷涂工艺适应性。 溶胶 - 凝胶法制备的 TiO2 粉末微观结构为不规则形, 经过热处理后由无定形态 转变为锐钛矿相。 冷喷涂 TiO2 涂层晶体结构及涂层内部 TiO2 颗粒的微观形貌均与溶胶 - 凝胶 TiO2 粉末保持一致。 冷喷涂 TiO2 涂层的光催化活性受原始喷涂粉末影响, 当原始喷涂粉末的光催化活性高时, 冷喷涂 TiO2 涂层的光 催化活性也较高。     

Effects of Rare Earth Elements on Photocatalytic Antibacterial Properties of Nanometer TiO2 Powders

Nanometer Ce/TiO2 functional materials with photocatalystic antibacterial properties were prepared by dipping TiO2 nanometer powders into RE( NO3 )·nH2O solutions, filtrating, drying and heat treatment, and the enhancement mechanisms of Ce on the nanometer TiO2 were studied by electronic spin resonance(ESR) The results show that TiO2 for photocatalystic antibacterial properties is strengthened evidently by adding Ce, which has a high efficiency of photocatalystic antibacterial properties with the light extent of visible light and ultraviolet radiation. The basic reason for obtaining the strengthened result is that the effective wave length of photocatalystic properties of TiO2 can be expanded to visible light area with the induction of the rare earth elements, whether or not ultraviolet light exists, nanometer TiO2 can produce a great deal of hydroxylic radical(·OH) by treating with rare earth elements.     

La-TiO2中性水溶胶光催化性能

以偏钛酸为原料,制备了锐钛矿型纳米TiO2中性水溶胶,采用XRD、SEM、TEM、吸收光谱以及光电流响应等对TiO2水溶胶进行表征.结果发现,TiO2粒径约为11.6 nm,稀土元素La掺杂,使得水溶胶的吸收光谱阙值红移至545 nm,可见光响应能力明显增强.光催化降解试验表明,溶胶对甲醛具有快速降解能力,当甲醛浓度≤3×10-6时,24 h可以降解至国家标准范围以内,但降解过程受环境湿度影响明显.     

SO2 poisoning and regeneration of Mn-Ce/TiO2 catalyst for low temperature NOx reduction with NH_3

SO2 poisoning and regeneration of Mn-Ce/TiO2 catalyst prepared by a novel co-precipitation method for low temperature selective catalytic reduction (SCR) of NOx with ammonia were investigated in this study. When 700 ppm SO2 was fed in, the Mn-Ce/TiO2 catalyst had good resistance to SO2, but the deactivation of Mn-Ce/TiO2 poisoned by SO2 still occurred. The NO conversion of Mn-Ce/TiO2 (the molar ra-tio of Ce to Ti is 0.075) catalyst decreased from 92.5% to 34.6% in 13 h. Characterizations of fresh and SO2-poisoned Mn-Ce/TiO2 catalysts were carried out by Brunauer-Emmett-Teller method (BET), ion chromatography (IC), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The characterized results indicated that the deposition of sulfates and nitrates on the surface made the catalyst deactivated. Water washing, thermal regeneration and reductive regeneration were used to regenerate the deactivated Mn-Ce/TiO2. And water washing showed best performance on the regeneration of poisoned catalysts, especially with ultrasonic vibration. The Mn-Ce/TiO2 catalyst showed high stability under a series of deactivation-regeneration experiments for ten cycles.     

Preparation and Fluorescence Properties of TiO_2∶Eu Nano-Materia ls

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