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1.
Titania-supported tungsten oxide catalysts with different W loadings up to 9 wt. % and calcined at different temperatures have been prepared and characterized. It is found that W hinders the initial sintering of anatase, providing thermal stability. The interaction of W with TiO2 and the amount of hydroxy groups present on the surface can limit diffusion, thus reducing the sintering rate.  相似文献   

2.
A novel N-doped TiO2 (N1-N2-TiO2) with substitutional and interstitial N impurities simul-taneously was successfully synthesized.The catalyst was characterized by X-ray diffraction,X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence, and electron paramagnetic resonance. The results demonstrated that the nitrogen was substi-tuted for the lattice oxygen atoms, and was also interstitially doped into the TiO2 lattice.The photocatalytic tests indicated that the N1-N2-TiO2 showed the highest photocatalytic activities of all the N-doped TiO2 under visible light, attributing to the synergetic effect of substitutional and interstitial nitrogen of N-doped TiO2.  相似文献   

3.
水热法合成掺杂铁离子的小管径TiO2纳米管   总被引:17,自引:0,他引:17       下载免费PDF全文
碳纳米管这种一维结构的新材料的发现为物理、化学、材料科学和纳米科学开辟了全新的研究领域.近年来,非碳无机类富勒烯(Inorganic Fullerenelike,简称IF)纳米管也受到人们的广泛关注.  相似文献   

4.
花状TiO2分级结构的可控合成与其光催化性能   总被引:1,自引:0,他引:1  
采用水热法可控合成了花状TiO2分级结构材料,运用扫描电镜、透射电镜、X射线衍射、N2物理吸附-脱附等手段,对其进行了表征,系统研究了NaOH用量、H2O2浓度、HNO3浓度、反应温度及时间等因素对所得样品形貌的影响,并评价了它们的光催化性能.结果表明,花状TiO2分级结构为锐钛矿相,颗粒大小均一;随制备条件的变化,构成花状TiO2分级结构的基元结构分别为纳米线、纳米片,纳米线直径约25nm,纳米片厚度不足10nm;该样品具有较高的比表面积,表现出良好的单次光催化活性与重复使用性能.  相似文献   

5.
VOx/TiO2 and MoOx/TiO2 catalysts with the addition of Re (Re/V or Mo = 0.5) were synthetized and tested in oxidative dehydrogenation of propane and in reduction by propane. XPS measurements showed depletion of the surface in Re. The Re additive does not affect the total conversion of propane, but increases the selectivity to propene. The effect is more pronounced for the MoOx/TiO2 catalyst. The increase in the selectivity to propene is accompanied with the increase in the reducibility of the catalysts.  相似文献   

6.
The TiO2-doped ZnO microtubes have been successfully fabricated via a wet chemicalmethod, using zinc chloride and titanium sulphate as the starting materials. The as-synthesized products were characterized by X-ray diffraction, field emission scanning electronmicroscopy and room temperature photoluminescence measurement. The photocatalytic ac-tivity in degrading methyl orange was measured with a UV-Vis spectrophotometer. The pure ZnO microtubes exhibit an exact hexangular hollow structure with a diameter of about 700 nm, a length of 3 μm and a wall thickness of about 40 nm. The TiO2-doped ZnO microtubes with TiO2/ZnO ratio less than 5% have the same dimension with the pure ZnO microtubes, a smooth column shape, not a hexangular structure. The growth of ZnO may be inhibited by the more Ti4+ doped into ZnO structure to achieve a small dimension or a multiphase. The crystallinity of ZnO microtubes decreases with increasing TiO2 content, and then a multiphase containing ZnO, Ti3O5 and TiO occur when the TiO2/ZnO ratio is more than 5%. The UV emission intensity of the TiO2-doped ZnO obviously increases and then tends to decrease with TiO2/ZnO ratio increasing. The photocatalytic properties of the TiO2-doped ZnO microtubes are very effcient in degrading organic dyes of methyl orange and are well identical with its PL properties and the crystallinity.  相似文献   

7.
A nanocomposite photocatalyst composed of AlFeO3 and TiO2 is prepared, and characterized through X-ray diffraction. Application of the nanocomposite for the photodegradations of eosin dye and methyl orange gives an improved photoactivity compared with TiO2-only nanomaterials. The optimal concentration of AlFeO3 in the composite is about 1.0 wt% under UV excitation, and 9.0 wt% under sunlight excitation for the improved photoactivity. Furthermore, this nanocomposite is more active for eosin photodegradation if natural sunlight rather than UV is used. This may be due to the reason that adding AlFeO3 nanoparticles into TiO2 matrix can promote the separation of photogener-ated charge carriers, and extend the photoresponse of TiO2 toward visible region, which results in an increase in the solar energy utilization efficiency.  相似文献   

8.
TiO2/Gd2O3纳米粉体的制备、表征及光催化活性   总被引:4,自引:0,他引:4       下载免费PDF全文
利用酸催化的溶胶-凝胶法制备了纯TiO2和Gd3+(0.5wt%)掺杂的TiO2纳米粉体,采用XRD、BET、XPS、紫外-可见漫反射谱(DRS)和表面光电压谱(SPS)等技术进行了表征;以亚甲基蓝(MB)的光催化降解为探针反应,评价了其光催化活性;探讨了Gd3+掺杂对TiO2纳米粉体的光催化活性的影响机制。结果表明,TiO2/Gd2O3纳米粒子对MB溶液的光催化活性提高到纯TiO2的1.5倍。掺杂Gd3+可以强烈抑制TiO2由锐钛矿相向金红石相的转变;阻碍TiO2晶粒的生长;提高高温组织稳定性,改善粉体的表面织构特性;形成光生电子的浅势捕获陷阱,抑制e-/h+复合,这些因素共同作用最终导致TiO2/Gd2O3纳米粉体的光催化活性明显提高。XPS分析结果证实,掺杂Gd3+导致粉体的表面羟基含量降低。由于产生了量子尺寸效应,复合粉体的紫外吸收带边蓝移,光的吸收能力略有降低。  相似文献   

9.
以掺杂了不同TiO_2含量的Al_2O_3作为载体,通过等体积浸渍法制备了一系列不同TiO_2含量的CuMnCe/TiO_2-Al_2O_3催化剂,用BET、H_2-TPR、XRD和XPS表征技术对催化剂物理化学性质进行表征,并考察了催化剂在含甲烷气脱氧反应中的催化性能。结果表明,在载体中添加TiO_2对催化剂活性组分的晶相结构和分散度没有明显影响;但有效改善了Al_2O_3载体抗烧结能力;增加了CuMnCe/Al_2O_3催化剂表面Ce~(3+)/(Ce~(3+)+Ce~(4+))的相对含量,从而提高了活性氧的移动性,且使催化剂表面可氧化还原物种含量和表面吸附氧Osur/(Osur+Olatt)的含量增多。有效改善了催化剂在含甲烷气催化燃烧脱氧上的催化活性。其中,CuMnCe/4%TiO_2-Al_2O_3表现出最优的催化活性,在387℃时可使含甲烷气中氧气的转化率达到100%。  相似文献   

10.
Using polystyrene(PSt) particles as template,PSt/TiO2 composite particles with AgCl incorporation were prepared through hydrolysis of tetrabutyl titanate in the presence of AgNO3 and NaCl.AgCl doped TiO2 hollow particles were successfully prepared with the PSt/TiO2 composite microspheres pretreated at 180℃followed by calcination.The morphology of PSt/TiO2 particles and the crystal structures of the AgCl doped TiO2 hollow particles were characterized.The photocatalytic activity of the doped TiO2 hollow particles in degradation of Rhodamine B was tested under UV and visible lights and compared to that with Ag doped TiO2 particles.The results showed that TiO2 hollow particles,either doped with Ag or AgCl,demonstrated higher photocatalytic activity than the pure TiO2 particles.This enhancement in photocatalytic activity was more significant with AgCl doped TiO2 than that with Ag doped,and more distinct when the degradation was done under visible light than that under LTV light.  相似文献   

11.
The objective of this work was to study the kinetics of methane combustion for a series of Fe2O3/TiO2 catalysts. An increase in activity is observed as iron loading increases, and can be attributed to an increase of surface coverage by Fe2O3 species. Kinetic studies revealed that the reaction orders with respect to methane, oxygen, carbon dioxide and water are 1, 0, 0 and -1 respectively. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

12.
This article describes the preparation of mesoporous rod-like F-N-codoped TiO2 powder photocatalysts with anatase phase via a sol-gel route at the temperature of 373 K, using cetyltrimethyl ammonium bromide (CTAB) as surfactant. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra (UV-vis DRS). The results showed that the photocatalysts possessed a homogeneous pore diameter and a high surface area of 106.3-160.7 m3 g−1. The increasing CTAB reactive concentration extended the visible-light absorption up to 600 nm. The F-N-codoped TiO2 powders exhibited significant higher adsorption capacity for methyl orange (MO) than that of Degussa P25 and showed more than 6 times higher visible-light-induced catalytic degradation for MO than that of P25.  相似文献   

13.
锐钛矿型多孔TiO2薄膜的溶解法制备及性能表征   总被引:2,自引:0,他引:2  
在具有锐钛矿晶粒的TiO2溶胶中加入苯丙乳液粒子,使用该混合液浸渍提拉涂膜,然后利用甲苯将薄膜中的苯丙乳液粒子溶解去除,并通过重复涂膜,在室温下获得了具有良好多孔性的锐钛矿型TiO2薄膜。考察了多孔薄膜的表面形貌、光学性能、吸附性能和光催化性能。结果表明:随薄膜涂膜次数的增加,TiO2多孔薄膜的吸光度增大,透光率减小,光吸收边波长向长波方向移动。罗丹明B在TiO2多孔薄膜上的吸附量随涂膜次数的增加先升高,后降低;多次涂膜会在薄膜中产生半封闭的孔洞,经过长时间的毛细渗透等作用能进一步增加薄膜对罗丹明B的吸附。TiO2多孔薄膜通过吸附+光催化氧化的模式快速分解罗丹明B,其活性主要受到薄膜在光催化反应初期的吸附能力的影响。此外,TiO2的负载量、光的利用效率、以及光生电荷迁移及其分离等也是影响薄膜光催化活性的因素。  相似文献   

14.
利用共沉淀法和柠檬酸法制备YFeO3, 并以其为载体, 将TiO2溶胶负载在其表面, 制备了复合光催化剂TiO2/YFeO3. 在紫外灯的照射下, 考察对气相苯的降解效果并利用N2吸附、X射线衍射(XRD)、拉曼光谱、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、UV-Vis漫反射光谱等手段对催化剂进行了表征. 结果表明, 以共沉淀法制备的YFeO3为载体的复合催化剂, 180 min内苯的降解率达到44.7%, 表现出更好的光催化活性. 两种方法制备的YFeO3均为斜方晶相, TiO2分散在载体的表面, 并与YFeO3存在一定的相互作用; 两种复合催化剂均具有较窄的带隙能.  相似文献   

15.
Nano-composite of Fe-doped anatase TiO2 nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO2 mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO2 nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO2 based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light (λ>420 nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications.  相似文献   

16.
TiO_2载体掺杂对Mn-Ce/TiO_2催化剂低温脱硝性能影响研究   总被引:1,自引:0,他引:1  
以TiO_2、TiO_2-Al_2O_3及TiO_2-SiO_2为载体,选取Mn为活性组分,Ce为活性助剂,采用分布共混法制备低温SCR催化剂,分析了TiO_2载体掺杂Al_2O_3、SiO_2改性后对Mn-Ce/TiO_2催化剂低温脱硝活性的影响,运用BET、SEM、XRD、H2-TPR以及NH_3-TPD等测试手段对催化剂进行了表征。结果表明,TiO_2载体经掺杂改性后,Mn-Ce/TiO_2催化剂的比表面积、孔结构参数以及表面孔结构形貌均得到改善和提高;Mn-Ce/TiO_2-Al_2O_3和Mn-Ce/TiO_2-SiO_2催化剂中TiO_2的结晶度均有不同程度降低;经TiO_2载体掺杂改性后的催化剂表面低温还原峰面积及催化剂表面酸性位种类及酸性大小显著改善,这都有助于提高催化剂的脱硝活性。通过对TiO_2载体掺杂SiO_2和Al_2O_3改性后,催化剂的脱硝活性明显提高,反应温度在80-140℃时,催化剂SCR脱硝活性的顺序是:Mn-Ce/TiO_2-SiO_2M n-Ce/TiO_2-Al_2O_3M n-Ce/TiO_2。  相似文献   

17.
This study has demonstrated that the synthesis of TiO2 and V/TiO2 thin layers may be significantly improved and extended if microwave energy is employed during the drying and/or calcination step. Thin nanoparticulate titania layers were prepared via the sol-gel method using titanium n-butoxide as a precursor. As prepared films were then analyzed by means of various characterization techniques (Raman spectroscopy, UV/Vis, AFM, XPS) in order to determine their functional properties. The photocatalytic activities of prepared layers were quantified by the decoloring rate of Rhodamine B. All thermal treatments in microwave field were done in the same manner, by using an IR pyrometer in the microwave oven and monitoring the temperature of the heating. Nevertheless the microwave and thermally prepared materials were different. This in turn may lead to differences in their functional and also photocatalytic properties.  相似文献   

18.
高热稳定性纳米Au/TiO2催化剂的制备与表征   总被引:3,自引:0,他引:3  
吕倩  孟明  查宇清 《催化学报》2006,27(12):1111-1116
 采用三嵌段共聚物聚乙醚-聚丙醚-聚乙醚EO20PO70EO20 (P123)为有机模板剂合成了介孔TiO2载体,用沉积-沉淀法制得Au/TiO2催化剂. 运用N2 吸附-脱附、 X射线衍射、 X射线光电子能谱和高分辨电镜技术对催化剂的结构与形貌进行了表征. 采用P123模板剂合成的TiO2具有较均匀的介孔结构,孔径集中在6.1 nm附近,负载金后,其介孔结构保持良好,但孔径下降至5.4 nm. 400 ℃焙烧后,介孔TiO2负载的Au催化剂中Au主要以金属态存在. 负载在三种TiO2载体(介孔TiO2、溶胶-凝胶法合成的TiO2和工业TiO2)上的Au晶粒大小和分散度差异较大,其中介孔TiO2载体更有利于金的分散,以该载体制备的催化剂400 ℃焙烧后金的晶粒尺寸在1~5 nm范围内,催化剂显示了很好的CO氧化活性和抗热稳定性,即使在420 ℃焙烧,其室温下CO的转化率也在90%以上. 而溶胶-凝胶法制备的TiO2和工业TiO2负载的纳米金催化剂中,金晶粒尺寸约为10 nm,催化剂的CO氧化活性和抗热稳定性较差.  相似文献   

19.
YFeO3 was prepared by coprecipitation method and citric acid method, and TiO2/YFeO3 heterosystem photocatalysts were synthesized by loading TiO2 sol on the surface of YFeO3via sol-gel method. Their photocatalytic activities were evaluated by the decomposition of gaseous benzene under UV light illumination. The prepared photocatalysts were characterized by nitrogen adsorption-desorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Vis diffuse reflectance spectroscopy. Results revealed that the heterosystem photocatalysts prepared by coprecipitation method showed higher activity, and the maximum conversion of benzene could reach 44.7% within 180 min. The YFeO3 samples prepared from coprecipitation method and citric acid method were absolutely in orthorhombic phase. The deposited titania was dispersed on the surface of carrier and a certain interaction existed between TiO2 and YFeO3. The two heterosystems photocatalysts had narrow band-gap energies.  相似文献   

20.
二氧化钛纳米管由于其特殊的结构和优异的性能,在很多领域都有着重要的应用前景。阳极氧化法是制备二氧化钛纳米管的一种主要方法。近来,在阳极氧化法中使用有机电解液来制备二氧化钛纳米管取得了非常显著的效果。与传统的水溶性电解液相比,其深宽比和光电转换效率有了很大的提高。本文主要介绍了二氧化钛纳米管的阳极氧化原理以及有机电解液在阳极氧化法中对二氧化钛纳米管生长过程的影响。  相似文献   

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