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1.
2.
Body-centered-cubic type CuPd nanoalloys were synthesized by a chemical reduction method. Photocatalytic hydrogen evolution and nitrate reduction were simultaneously examined over CuPd nanoalloys deposited on TiO(2) (CuPd/TiO(2)). The efficiency of hydrogen evolution over CuPd/TiO(2) was better than that over Pd/TiO(2). As for nitrate reduction, ammonia was selectively (78%) produced with hydrogen generated photocatalytically over CuPd/TiO(2). The continuous generation of nascent hydrogen atoms on the surface of the CuPd nanoalloy, where Cu and Pd are homogeneously mixed, led to the high selectivity for ammonia.  相似文献   

3.
Nanostructures of Sb-doped ZnO with 0.00, 0.03, 0.06, 0.10 and 0.15 mol fractions of Sb+3 ions were prepared by a one-pot method in water under microwave irradiation for 5 min. Powder X-ray diffraction studies display that the nanostructures are excellently crystallized in the form of Wurtzite hexagonal crystalline phase and doping Sb+3 ions does not change structure of ZnO. Moreover, size of the nanostructures decreases with increasing mole fraction of Sb+3 ions. Scanning electron microscopy and transmission electron microscopy images show that morphology and size of the nanostructures are changing with mole fraction of the dopant. In Fourier transform infrared spectra, intensity of the characteristic peak corresponding to Sb–O bond gradually increases with mole fraction of Sb+3 ions. UV–vis diffuse reflectance spectra of the nanostructures are similar to each other and they have a maximum of about 357 nm. Photocatalytic activity of the nanostructures was investigated by degradation of methylene blue under UV irradiation. For the nanostructures with 0.10 mol fraction of Sb+3 ions, the degradation rate constant increases nearly two times relative to pure ZnO. In addition, influence of various operational parameters on the degradation activity was investigated and the results were discussed.  相似文献   

4.
Comparative results (specific area, metallic dispersion, and activity in the carbon monoxide oxidation) on sol-gel and impregnated Pt/TiO2 catalysts are presented. In order to explain the important differences between the two preparations, among them high resistivity of sol-gel catalyst to sintering, the formation of anchored and/or partially buried particles into the support is proposed.  相似文献   

5.
Photocatalytic TiO2/glass nanoflake array films   总被引:1,自引:0,他引:1  
A new approach for the fabrication of oriented TiO2/glass nanoflake arrays has been developed. The ceramic nanoflake array was formed on a glass substrate via a simple, low temperature, and one-step hydrothermally induced phase separation approach without using any templates or additives. The factors affecting the formation of ceramic nanoflakes were examined by various characterization techniques. The results showed that the leaching of the soluble phase from the glass surface through hydrothermal processes resulted in oriented uniform ceramic nanoflake arrays. Electron microscope observations revealed that the nanoflakes formed a continuous porous three-dimensional-network array with a large surface-to-volume ratio. In addition, an anatase TiO2 film was successfully coated onto the nanoflake array by the sol-gel method. The TiO2/glass nanoflake array exhibited high activity for the photocatalytic degradation of acetone and for photoinduced hydrophilic conversion. Such enhancements were attributed to the beneficial effects of the new continuous porous three-dimensional-interconnected nanoflake network and its surface geometrical nanostructure. The present approach provides a convenient route to modify a photocatalytic coating with a porous nano-architectured substrate. This opens extensive new opportunities in the design of semiconductor/ceramic nanostructural array thin films with unusual properties for future optical and electronic applications.  相似文献   

6.
The effect of different nucleation agents such as ZrO2 and TiO2 was investigated for a first time with respect to their crystallisation behaviour in the glass system BaO-SrO-ZnO-SiO2. In all studied glasses, a Ba1-xSrxZn2Si2O7 (0.1 ≤ x ≤ 0.9) solid solution crystallized. This phase was first described in 2015 to possess a similar structure as the high temperature phase of BaZn2Si2O7 and a thermal expansion close to zero or even negative. It may find applications e.g. as cook panels, telescope mirrors, and furnace windows. Kinetic parameters of the crystallisation process were determined by supplying different heating rates in a differential scanning calorimeter (DSC). The results were evaluated using the equations of Ozawa and Kissinger with respect to the activation energies. Furthermore, the Ozawa method was used for the determination of Avrami parameters, which provides further information on the nucleation and crystallisation processes. Scanning electron microscopy including electron backscatter diffraction (EBSD) was used to characterise the microstructure, to determine the crystallite size and the crystal orientation. For the characterisation of the occurring crystalline phases, X-ray diffraction was used.  相似文献   

7.
以含有Au和ZnO纳米颗粒的氢氧化钛溶胶作为成膜液,通过浸渍-提拉及灼烧处理在导电玻璃表面制备Au/ZnO/TiO2复合薄膜.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)等方法对所得产物进行表征.结果表明,Au和ZnO纳米颗粒均匀地分布在多孔TiO2薄膜上,通过TiO2、ZnO和Au三组分的协同效应促进了光吸收和电荷分离,使Au/ZnO/TiO2复合薄膜具有较好的光电转换性质,可用作太阳能电池材料.  相似文献   

8.
A microwave-assisted facile method for the preparation of various ureas, cyclic ureas, and urethanes has been developed that affords nearly quantitative yield of products at 120 °C (150 W), 71 kPa within 10 min using ZnO as a catalyst. The enhanced selectivity in this reaction is attributed to the deployment of ZnO whose absence results in poor yield and the generation of byproducts.  相似文献   

9.
采用共沉淀法制备了ZnO/TiO2和La离子掺杂La-ZnO/TiO2催化剂,利用XRD,XPS和uV-vis对催化剂进行了表征;在光反应器中进行了ZnO/TiO2和La-znO/TiO2催化降冰片二烯光异构化生成四环烷的反应。研究了ZnO和La离子掺杂对催化剂的结构、表面组成、吸光性能及催化性能的影响。结果表明,ZnO/TiO2复合可形成锐钛矿和ZnTiO3混晶结构,从而提高了催化剂的活性;La离子掺杂能提高表面Ti-OH物种含量和催化剂的吸光性能,并提高ZnO/Ti02的催化活性。10%La掺杂的ZnO/TiO2催化活性最佳,反应12h四环烷的收率达93.58%,选择性为100%。当La的掺杂量达到30%时,催化剂中Ti-OH含量明显减少,吸光强度最低,活性下降。  相似文献   

10.
We report on the synthesis of ZnO and TiO2 nanoparticles by solution-phase methods, with a particular focus on the influence of experimental parameters on the kinetics of nucleation and coarsening. The nucleation rate of ZnO from the reaction between ZnCl2 and NaOH in ethanol was found to increase with increasing precursor concentration, while the coarsening rate is independent of precursor concentration up to a threshold concentration. The nucleation rate of ZnO from Zn(OOC-CH3)2 and NaOH in n-alkanols was found to decrease with decreasing chain length, which is explained by the increase of the dielectric constant of the solvent. Due to the larger solubility of ZnO, nucleation is significantly slower than that observed in the case of TiO2. TiO2 nanoparticles coarsen according to the Lifshitz-Slyozov-Wagner model for Ostwald ripening. We also show that using amorphous titania as a base material, pure anatase and brookite nanoparticles can be synthesized.  相似文献   

11.
Although synthetic investigations of inorganic nanomaterials had been carried out extensively over the past decade, few of them have been devoted to fabrication of complex nanostructures that comprise multicomponents/phases (i.e., composite nanobuilding blocks), especially in the area of structural/morphological architecture. In this work, nanobelts of a protonated pentatitanate (H(2)Ti(5)O(11).H(2)O) were synthesized hydrothermally for the first time. Two technologically important transition-metal-oxides TiO(2) and ZnO were then grown respectively or sequentially onto the surface of the as-prepared nanobelts in aqueous mediums. With a main emphasis on organizational manipulation, the present investigation examines general issues of morphological complexity, synthetic interconvertibility, and material combinability related to fabrication of inorganic nanocomposites. Using this model material system, we demonstrate that complex binary and tertiary composite building blocks of TiO(2)/H(2)Ti(5)O(11).H(2)O, ZnO/H(2)Ti(5)O(11).H(2)O, ZnO/TiO(2)/H(2)Ti(5)O(11).H(2)O, and ZnO/TiO(2) can be architected stepwise in solution. Structural features of these nanocomposites have also been addressed.  相似文献   

12.
Yao  Lili  Sun  Yu  Weng  Wenjian  Lin  Jun  Cheng  Kui 《Journal of Sol-Gel Science and Technology》2018,86(2):459-467

In the present study, TiO2/ZnO composite nanodot films were prepared and the effects of Zn incorporation on light-induced cell detachment were investigated. The nanodots films, which were successfully synthesized by phase-separation-induced self-assembly method, were characterized on the morphology, composition, microstructure, and other properties, and evaluated on cell compatibility and cell detachment performances as well. Live-dead staining was used to study the viability of cell sheet detached by light illumination. Results shows that with the increasing of introduced Zn, the band gap widened and the absorbance in UV region increased, while the crystallinity and performance of light-induced hydrophilicity weakened. All the nanodots films showed good cell compatibility and cell detachment performance induced by light. The nanodots film which had a Zn/Ti molar ratio of 0.03 showed the highest detachment ratio of 91.0% after 20?min ultraviolet illumination. The prepared TiO2/ZnO composite nanodots films could be helpful in optimizing light-induced cell detachment behavior.

  相似文献   

13.
Ordered porous TiO2 films, including TiO2 nanotube arrays, are fabricated by a sol-gel dip-coating approach via ZnO nanorod templates obtained from aqueous solution approach. The results indicate that the morphologies of ordered porous TiO2 films have been great affected by the sol-gel dip-coating cycle number. Open-ended TiO2 nanotube arrays can be obtained in optimum dip-coating cycle numbers. The TiO2 nanotubes with the inner diameter matching well with the diameters of ZnO nanorods, are well assembled and separate each other. When the cycle number is less than this optimum value, no intact porous TiO2 film can be obtained. As the cycle number is larger than this optimum value, an ordered porous TiO2 film with many throughout holes is formed. The evolutive mechanism of ordered porous TiO2 films is proposed.  相似文献   

14.
不锈钢基底上TiO2薄膜型光催化剂的制备和化学结构   总被引:23,自引:0,他引:23  
朱永法  张利  王莉  付艳  曹立礼 《化学学报》2000,58(4):467-472
采用钛酸正丁酯作为前驱体,通过溶胶-凝胶法在不锈钢基片上制备了TiO2纳米薄膜。利用俄歇电子能谱(AES)和紫外反射光谱等研究手段,对TIO2薄膜的化学结构及基底材料界面相互作用进行了系统研究。结果发现,在不锈钢基底上形成的TiO2薄膜与基底材料发生了明显的界面扩散反应。在TiO2薄膜的形成过程中,不锈钢中Fe元素向TiO2薄膜层扩散,并与从大气氛中扩散到界面的氧发生化学反应,形成铁氧化物界面过渡层。界面氧化过程,导致了Fe向样品表面的偏析和扩散。在高温热处理过程中,Fe可以扩散到TiO2薄膜的表面。薄膜催化剂的紫外反射光谱表明,界面扩散反应导致了Fe扩散进入TiO2薄膜的晶格,从而改变了薄膜催化剂的光吸收性能。  相似文献   

15.
Novel ZnO/TiO(2) composite nanofibers were fabricated by an electrospinning method and showed excellent antimicrobial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus under UV irradiation and in the absence of light.  相似文献   

16.
玻璃负载TiO2膜光催化降解2,4-二氯苯酚   总被引:14,自引:0,他引:14  
玻璃负载TiO2膜光催化降解2;4-二氯苯酚  相似文献   

17.
Active reaction centers for ammonia on titanium oxyhydroxide were explored to direct the search for an efficient sol-gel method for the synthesis of a titanium oxynitride (TiO2-xNx) sample with an efficient responsiveness to the visible light constituting a main part of the solar spectrum. The results lead to the conclusion that the site giving IR bands at around 2195 cm(-1) for the adsorbed CO molecules at 300 K is a reactive site and behaves as Lewis acid site in the coordination environment of distorted five-coordinate Ti4+ ions. Ammonia molecules are adsorbed on such a site to form -NH2 and -OH species during the heat treatments at a temperature above 373 K, and they are ultimately incorporated into the TiO2 lattice as nitride through the dehydration at higher temperatures of up to 723 K, resulting in the formation of an anatase type of TiO2-xNx.  相似文献   

18.
Many types of TiO2-SiO2 (Ti:Si=50:50 mol%) were prepared by the sol-gel procedure with and without 2-methyl-2, 4-pentanediol (MPD) as an organic ligand. The effect of MPD on the gel structure and the properties of the TiO2 crystals were studied by XRD and raman spectroscopy, and the effect of the sol standing time on the properties of the TiO2 crystals were also studied by XRD spectroscopy. In the gels with MPD, anatase of TiO2 appeared at approximately 580°C, and the crystal structures were similar despite the difference in the gel preparation procedure. The titania gels with MPD were presumed to be dispersed in the silica gel matrix without any Ti-O-Si bond. In the presence of MPD, the formation of titania gels is controlled and the specified TiO2 crystal is produced.  相似文献   

19.
《化学通报》2010,73(11):1012-1017
以微米尺寸的花状和棒状ZnO为载体,利用表面吸附层水解方法,制备了具有微/纳米结构的ZnO/TiO2复合光催化剂。采用SEM、XRD、EDS和UV对其形貌、结构、表面组成等进行了表征。结果表明,在棒状或花状微米尺寸ZnO表面能形成均一尺寸的TiO2纳米粒子。复合物中表面TiO2含量与Ti(OC4H9)4添加量呈正相关性。得到的复合物为纤锌矿型氧化锌和锐钛矿型氧化钛复合物。对不同组成ZnO/TiO2复合物的光催化活性进行了初步研究。  相似文献   

20.
Tungsten carbide/titanium oxide (WC/titanium dioxide (TiO2)) particles are prepared by microwave-assisted heating in conjunction with ionic liquid and the subsequent reduction–carbonization. The platinum particles are loaded on the WC/TiO2 to prepare Pt-WC/TiO2. The electrocatalytic performances of the Pt-WC/TiO2 toward methanol oxidation are evaluated by cyclic voltammetry, chronoamperometry, and the CO stripping tests. It is found that electrocatalytic activity of Pt-WC/TiO2 is enhanced by adding ionic liquid (IL) during sample preparation. The results indicate that better performance toward methanol oxidation and higher tolerance to CO are achieved with an optimal addition of 1.5 ml 1-methyl-imidazoliumtetr-afluoroborate for preparing Pt-WC/TiO2. To investigate the function of IL, the phase structure and morphology of samples at different stages during preparation are examined by X-ray diffraction and transmission electron microscopy. Ionic liquid is found to act as not only a good solvent offering the excellent microwave absorption, but also a structure-directing agent to control the morphology and structure of sample, which affect the activity of the final catalysts.  相似文献   

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