纳米结构TiO2/PS及TiO2空心球的自组装与表征

以TiCl₄的盐酸溶液配制的TiO₂溶胶为前驱体, 以聚苯乙烯微球为载体, 在表面活性剂存在下, 通过逐层自组装技术制备了纳米结构TiO₂/PS及TiO₂空心球. 利用XRD, SEM, TG-DTA等对复合颗粒进行了表征. 研究表明: 纳米结构TiO₂/PS的组成、结构、形貌和粒度可通过溶胶酸度、组装时水解反应温度、煅烧温度、硫酸根的加入量来控制.     

纳米结构TiO2/PS及TiO2空心球的自组装与表征

以TiCl₄的盐酸溶液配制的TiO₂溶胶为前驱体, 以聚苯乙烯微球为载体, 在表面活性剂存在下, 通过逐层自组装技术制备了纳米结构TiO₂/PS及TiO₂空心球. 利用XRD, SEM, TG-DTA等对复合颗粒进行了表征. 研究表明: 纳米结构TiO₂/PS的组成、结构、形貌和粒度可通过溶胶酸度、组装时水解反应温度、煅烧温度、硫酸根的加入量来控制.     

硅球多层模板溶胶浸渍法制备有序多孔TiO2薄膜

采用垂直沉积法组装了平均球径为188 nm的三维有序二氧化硅微球阵列。以该阵列为模板，通过在TiO₂前驱体溶胶中多次浸渍热处理循环，随后采用超声辅助的NaOH溶液腐蚀去除硅球模板，制备了>20层厚的反转结构的二氧化钛多孔膜。该二氧化钛薄膜在550 ℃下热处理20 h其多孔结构保持不变，表明采用此方法制备的二氧化钛多孔膜具有较好的热稳定性。X射线衍射图表明550 ℃下热处理得到的是具有锐钛矿结构的二氧化钛多孔膜。透光光谱显示了光子带隙出现在～400 nm。通过SEM观察，二氧化钛多孔膜     

锐钛矿型多孔TiO2薄膜的溶解法制备及性能表征

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。     

TiO2薄膜空气-水界面自组装的研究

本文采用十二烷基磺酸钠(SDS)作模板并以明胶作稳定剂，在空气-水的界面上组装TiO₂薄膜。结果表明，采用明胶稳定的薄膜具有良好的机械强度。采用X射线角度扫描技术(AD)原位检测薄膜的结构，并用X射线宽角衍射(WAXS)和小角衍射(SAXS)技术对经后续处理的TiO₂薄膜结构进行了表征。研究发现，明胶的加入可显著降低薄膜中TiO₂颗粒细度；经洗涤后，此复合薄膜材料可转换成纯层状的TiO₂薄膜。分析了明胶稳定TiO相似文献   

具有稳定可见光催化活性TiO2薄膜的常温制备

采用溶胶-凝胶法，通过钛酸丁酯水解制备了具有锐钛矿-金红石-板钛矿混晶晶粒的TiO₂溶胶。以四磺酸酞菁铜(CuTsPc)为敏化剂，经水浴加热后获得具有可见光响应活性的TiO₂溶胶。使用该溶胶浸渍-提拉涂膜，在室温下晾干即可得到酞菁敏化的TiO₂薄膜(CuTsPc-TiO₂)。对敏化溶胶的制备条件及薄膜的性能进行了考察，并探讨了CuTsPc的负载机理。结果表明:延长水浴时间或提高TiO₂溶胶中的CuTsPc浓度有利于增大薄膜中CuTsPc的负载量。随着薄膜中CuTsPc量的增加，薄膜的可见光催化活性增强，但CuTsPc负载过多又会导致薄膜光催化活性降低。CuTsPc通过静电作用在TiO₂胶粒表面发生吸附，从而实现在薄膜中均匀、牢固的负载，保证了CuTsPc-TiO₂薄膜在循环使用过程中的稳定性。     

TiO2一维纳米材料及其纳米结构的合成

本文对合成TiO₂一维纳米材料及其有序纳米阵列的阳极氧化法、模板法以及水热法进行了全面而系统的评述，着重介绍了它们的最新研究进展。阳极氧化法能制备牢固负载于基体上的TiO₂纳米管阵列，这有助于构筑TiO₂纳米结构及其在纳米器件上的应用；与多种制备技术如溶胶－凝胶工艺、电化学沉积以及原子层沉积等相结合，模板法可以合成出多种形貌的TiO₂纳米材料如纳米管、纳米线和纳米棒，并可以通过改变所用模板的微观尺寸来调控TiO₂一维纳米材料及其有序阵列的微结构参数；水热合成法可以制备出直径小且比表面积大的TiO2纳米管粉末。但从目前看来，该法还不能制备出牢固负载于基体上的有序纳米阵列。文章最后指出了TiO₂一维纳米材料及其有序纳米阵列合成中存在的问题及今后发展方向。     

简易模板剂法制备多级介孔TiO2微球及其在染料敏化太阳能电池中的性能

采用模板剂法一步合成分级结构的介孔TiO₂微球, 考察了烷基胺类模板剂中烷基链长度对介孔TiO₂微球合成及性能影响. 将其应用于染料敏化太阳能电池的光阳极半导体薄膜中, 得到了9.5%-10.1%的高能量转换效率. X射线衍射(XRD)、物理吸附仪(BET)、扫描电镜(SEM)等的分析结果表明: 分级结构介孔TiO₂微球的晶相为纯锐钛矿型; 介孔TiO₂微球表面粗糙, 的纳米粒子堆积形成, 使微球具有介孔性质和较适宜的比表面积. 介孔TiO₂微球堆积形成了利于物质扩散的通道并具有良好的光散射效果; 同时微球介孔粗糙表面保证了染料的大量吸附, 从而提高了电池的光电流. 通过电化学阻抗分析结果验证了分等级结构介孔TiO₂微球光阳极有利于电解液的传输和物质扩散的优异性能.     

骨架结构多孔TiO2薄膜增强染料敏化太阳能电池性能

以空心球状TiO₂为基体、以片状TiO₂为骨架,采用刮刀法制备了染料敏化太阳能电池的多孔TiO₂光阳极薄膜。光电转化效率测试结果表明,当作为骨架支撑材料的片状TiO₂含量为20wt%时,光阳极薄膜组装成太阳能电池的光电转化效率达到最高值4.53%,比商业P₂₅制备的无孔无骨架TiO₂薄膜电池(4.06%)及无骨架结构的多孔TiO₂薄膜电池(4.17%)的性能均有显著提高。当片状TiO₂的最佳含量为20wt%电池薄膜厚度为33μm时,太阳能电池光电转化效率进一步提升为7.06%。光电性能增强的原因是骨架结构有利于快速传输电子并增大染料吸附量。本研究通过设计制备具有骨架结构的多孔TiO₂薄膜为提高染料敏化太阳能电池性能提供了新的思路。     

骨架结构多孔TiO2薄膜增强染料敏化太阳能电池性能

以空心球状TiO₂为基体、以片状TiO₂为骨架,采用刮刀法制备了染料敏化太阳能电池的多孔TiO₂光阳极薄膜。光电转化效率测试结果表明,当作为骨架支撑材料的片状TiO₂含量为20wt%时,光阳极薄膜组装成太阳能电池的光电转化效率达到最高值4.53%,比商业P25制备的无孔无骨架TiO₂薄膜电池(4.06%)及无骨架结构的多孔TiO₂薄膜电池(4.17%)的性能均有显著提高。当片状TiO₂的最佳含量为20wt%电池薄膜厚度为33 μm时,太阳能电池光电转化效率进一步提升为7.06%。光电性能增强的原因是骨架结构有利于快速传输电子并增大染料吸附量。本研究通过设计制备具有骨架结构的多孔TiO₂薄膜为提高染料敏化太阳能电池性能提供了新的思路。     

Fabrication of Ordered TiO2 Porous Thin Films by Sol-Dipping PS Template Method

Monolayer polystyrene spheres (∼400 nm) array templates were assembled orderly on clean glass substrates by dip-drawing method from emulsion of PS and porous TiO₂ thin films were prepared by using sol-dipping template method to fill TiO₂ sol into the interstices among the close-packed PS templates and then annealing to remove the PS templates. The effects of TiO₂ precursor sol concentration and dipping time in sol on the porous structure of the thin films were studied. The results showed pore size of the ordered TiO₂ porous thin film depended mainly on PS size and partly on TiO₂ sol concentration. The shrinkage of pore diameter was about 10% for 0.2 M and 20% for 0.4 M TiO₂ sol concentrations. X-ray diffraction (XRD) spectra indicated the porous thin film was anatase structure. The transmittance spectrum showed that optical transmittance of the porous thin film kept above 70% beyond the wavelength of 430 nm. Optical band-gap of the porous TiO₂ thin film (fired at 550^∘;C) was 3.12 eV.     

Ordered porous ZnO thin films formed by dip-coating method using PS templates

Monolayer polystyrene spheres (∼400 nm) array templates were assembled orderly on clean glass substrates by dip-coating method from emulsion of polystyrene (PS). Porous ZnO thin films were also prepared by dip-coating method to fill the interstices among the close-packed PS templates with ZnO and annealing to remove the PS templates. Results showed that ZnO sol concentration and dipping time of PS templates in sol had great influences on the morphology of ordered porous ZnO thin films. There was a shrinkage ratio of about 30% from pore to PS. SEM observation showed that the PS array templates had face-centered cubic close-packing. X-ray diffraction (XRD) spectra showed the porous ZnO thin film was wurtzite structure. The optical transmittance decreased with decreasing wavelength of lights, but was kept above 80% beyond the wavelength of 550 nm. Optical band-gap of the porous ZnO thin film annealed at 500°C was 3.22 eV.     

The evolution of morphology of ordered porous TiO2 films fabricated from sol-gel method assisted ZnO nanorod template

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.     

Synthesis of Hollow Mesoporous TiO2 Microspheres with Single and Double Au Nanoparticle Layers for Enhanced Visible‐Light Photocatalysis

A facile method was used to prepare hollow mesoporous TiO₂ and Au@TiO₂ spheres using polystyrene (PS) templates. Au nanoparticles (NPs) were simultaneously synthesized and attached on the surface of PS spheres by reducing AuCl₄^? ions using sodium citrate which resulted in the uniform deposition of Au NPs. The outer coating of titania via sol‐gel produced PS@Au@TiO₂ core–shell spheres. Removing the templates from these core–shell spheres through calcination produced hollow mesoporous and crystalline Au@TiO₂ spheres with Au NPs inside the TiO₂ shell in a single step. Anatase spheres with double Au NPs layers, one inside and another outside of TiO₂ shell, were also prepared. Different characterization techniques indicated the hollow mesoporous and crystalline morphology of the prepared spheres with Au NPs. Hollow anatase spheres with Au NPs indicated enhanced harvesting of visible light and therefore demonstrated efficient catalytic activity toward the degradation of organic dyes under the irradiation of visible light as compared to bare TiO₂ spheres.     

Hydrothermal synthesis of 2D ordered macroporous ZnO films

The ZnO films with two-dimensional ordered macroporous structure were successfully fabricated through hydrothermal crystal growth of ZnO on the ZnO substrate covered with a monolayer of polystyrene (PS) spheres as template. The precursor solution of hydrothermal crystal growth of ZnO were prepared by equimolar solution of Zn(NO₃)₂·6H₂O and hexamethylenetramine (HMT). The confinement effect of the PS spheres template on the growth of ZnO nanorods and the influence of sodium citrate on the crystal growth of ZnO had been studied. The film surface morphology and the preferential growth of ZnO crystal were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Also, the photoluminescence spectrum of ZnO films had been measured, and the corresponding mechanism was discussed. __________ Translated from Chemistry, 2007, 70 (8): 587–592 [译自: 化学通报]     

Fabrication of Porous Metal Oxide Semiconductor Films by a Self-Template Method Using Layered Hydroxide Metal Acetates

Porous metal oxide (Co₃O₄, NiO, or ZnO) films were fabricated by a self-template method using layered hydroxide metal acetates (LHMA; metal = Co, Ni, or Zn) as templates. LHMAs were initially grown on glass substrates through a chemical bath deposition in methanolic-aqueous solutions of metal acetates at 60°C. The template films had a unique, nest-like morphology consisting of interlaced flake-like particles as a result of two-dimensional crystal growth of LHMAs in supersaturated solutions. The templates were successfully converted into porous Co₃O₄, NiO, or ZnO films by heating at 500°C for 10 min in air without microstructural deformation.     

Structural and optical properties of TiO2 thin films prepared by spin coating

Transparent semiconducting thin films of titanium oxide (TiO₂) were deposited on glass substrates by the sol–gel method and spin-coating technique. The physical properties of the prepared films were studied as a function of the number of spun-cast layers. The microstructure and surface morphology of the TiO₂ films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), with respect to the film thickness. The XRD analysis reveals that the films are polycrystalline with an anatase crystal structure and a preferred grain orientation in the (101) direction. The morphological properties were investigated by AFM, which shows a porous morphology structure for the films. The optical properties of the films were characterized by UV–Visible spectrophotometry, which shows that the films are highly transparent in the visible region and their transparency is slightly influenced by the film thickness, with an average value above 80 %. The dependence of the refractive index (n), extinction coefficient (k), and absorption coefficient (α) of the films on the wavelength was investigated. A shift in the optical band gap energy of the films from 3.75 to 3.54 eV, as a function of the film thickness, has been observed.     

TiO2 Thin Film with Varied Porous Structure Applied on the Degradation of Methylene Blue

In this study, porous TiO₂ thin films were prepared by the sol‐gel method employing polyethylene glycol 1000 (PEG 1000) as an organic template. Pore sizes were adjusted by varying the concentration of PEG 1000. The optimal PEG concentration range required to form TiO₂ films with a regular porous structure was investigated and was found to be 0.01–0.015 M. As the PEG 1000 concentration increased, the surface of these films became rougher because of larger pores. Degradation of methylene blue (MB) under UV irradiation was used to determine the photocatalytic activity of the films. In addition, the effect of the pH value of the MB solution on the films was evaluated by controlling its pH value at 5, 7, and 9. The results showed that the photocatalytic activity was correlated to the pore size and pore density of the thin films. TiO2 thin films possessing pore sizes in the diameter range of 35–85 nm exhibited the best conversion of 98% after 8 h of UV irradiation when the pH value was 7.