溶胶—凝胶法制备负载型TiO2膜的研究

本研究采用溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法制备了负载型ＴｉＯ２膜，并采用ＳＥＭ、压汞等实验手段对Ｔｉ（ＯＨ）４溶胶和ＴｉＯ２膜进行了表征。实验表明：Ｔｉ（ＯＨ）４溶胶制备过程中Ｈ２Ｏ／Ｔｉ＾４＋、Ｃ２Ｈ５ＯＨ／Ｔｉ＾４＋的比值，溶胶在支承管上浸涂的时间、次数以及凝胶煅烧升温速度和煅烧温度均是制备负载型ＴｉＯ２膜的重要因素。最终制得一种无裂纹、２０μｍ厚、孔径分布在５０￣３００ｎｍ之间的负载型ＴｉＯ２     

负载型SiO2无机膜的制备与表征

采用Ｓｏｌ－Ｇｅｌ法制备负载型ＳｉＯ_２无机膜，考察了有机粘结剂、处理温度对膜性能和结构的影响，并用ＳＥＭ、ＸＲＤ、孔分布和渗透性测定等方法对无机膜进行了表征。     

3—氨丙基三乙氧基硅烷对溶胶—凝胶法苯乙烯—顺丁烯二酸酐共聚物／Sio2杂化

用３－氨丙基三乙氧基硅烷（ＡＰＴＥＳ）作为偶联剂，通过溶胶－凝胶（ｓｏｌ－Ｇｅｌ）过程制得两相以共价键结合的透明苯乙烯－顺丁烯二酸酐共聚物／ＳｉＯ２杂化材料。通过ＦＴＩＲ分析等证实了材料有机相与无相相间是以共价键结合的。分析了材料热处理温度和分别用盐酸或氨水作催化剂时对材料溶胶分数的影响、偶联剂及其用量对溶胶－凝胶体系凝胶时间的影响、并研究了杂化材料中无机含量对材料折射率和Ｔｇ的影响。     

3-氨丙基三乙氧基硅烷对溶胶-凝胶法苯乙烯-顺丁烯二酸酐共聚物/SiO_2杂化材料的制备与性能的影响

用３ 氨丙基三乙氧基硅烷（ＡＰＴＥＳ）作为偶联剂，通过溶胶 凝胶（Ｓｏｌ Ｇｅｌ）过程制得两相以共价键结合的透明苯乙烯 顺丁烯二酸酐共聚物／ＳｉＯ２杂化材料．通过ＦＴＩＲ分析等证实了材料有机相与无机相间是以共价键结合的．分析了材料热处理温度和分别用盐酸或氨水作催化剂时对材料溶胶分数的影响、偶联剂及其用量对溶胶 凝胶体系凝胶时间的影响、并研究了杂化材料中无机含量对材料折射率和Ｔｇ的影响     

甲烷直接氧化制甲醇Ⅱ．催化膜反应器（CMR）

采用溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法制备了微孔结构均匀的“ＳｉＯ＿２／陶瓷”膜和“Ｍｏ－Ｃｏ－·Ｏ／ＳｉＯ＿２／陶瓷”催化功能膜，并用ＸＲＤ、ＳＥＭ和孔径测定等技术进行了表征。在常压、５００～７００℃的条件下，在催化膜反应器（ＣＭＲ）中考察了甲烷氧化制甲醇的反应。在相似的反应条件下（转化率为１．０％），用ＣＭＲ（甲醇选择性１１．２％）可获得较固定床反应器（甲醇选择性４．５％）高得多的甲醇选择性。     

甲烷直接氧化制甲醇：Ⅱ.催化膜反应器（CMR）

采用溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法制备了微孔结构均匀的“ＳｉＯ２／陶瓷”膜和“Ｍｏ－Ｃｏ－Ｏ／ＳｉＯ２／陶瓷”催化功能膜，并用ＸＲＤ、ＳＥＭ和孔径测定等技术进行了表征。在常压，５００～７００℃的条件下，在催化膜反应器（ＣＭＲ）中考察了甲烷氧化制甲醇的反应。在相似的反应条件下（转化率为１．０％），用ＣＭＲ（甲醇选择性１?．２％）可获得较固定床反应器（甲醇选择性４．５％）高得多的甲醇选择性。     

MoO3/TiO2 和WO3/TiO2 光催化分子氧氧化甲烷的活性

以Ｓｏｌ－Ｇｅｌ法制备的、表面积和孔径相近的含水ＭｏＯ３／ＴｉＯ２、ＷＯ３／ＴｉＯ２为催化剂,光催化分子氧氧化甲烷,初步研究表明,催化剂的活性高于ＴｉＯ２,且有少量的甲醇生成。     

锡(Ⅳ)-没食子酸-钒(Ⅳ)体系极谱吸附催化波的研究

在ｐＨ ２．３ 的氯乙酸盐缓冲液中，Ｓｎ（Ⅳ）－没食子酸（ＧＡ）－Ｖ（Ⅳ）体系产生一灵敏的吸附平行催化波，峰电位为－ ０．５０ Ｖ（ｖｓ．ＳＣＥ），二次导数峰高与锡浓度在６．７×１０－ １０～１．７×１０－ ６ ｍ ｏｌ／Ｌ 范围内呈良好线性关系，检测限达３×１０－ １０ ｍ ｏｌ／Ｌ。本文用循环伏安法等电化学方法研究了催化波的性质及电极反应机理。方法已成功地应用于罐头食品中微量锡的测定，结果满意。     

含对硝基偶氮苯胺生色团的键合型有机／无机复合材料的合成及其二阶非线性

以γ－缩水甘油氧丙基三甲氧基硅烷（ＫＨ５６０）作中间体,用溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法合成了含对硝基偶氮苯胺（ＤＯ３）生色团的新型键合型有机／无机复合非线性光学（ＮＬＯ）材料,在这种有机生色团与无机玻璃键合成形成的交联网络结构中,无机玻璃的刚性三维结构和优良的高温稳定性能有效抑制ＮＬＯ生色图的极化松驰,二次谐波售（ＳＨＧ）测量表明,合成的键合型聚合物膜的二阶非线性光学系数（ｄ３３）值达５．７９＊１０＾－７ｅｓｕ,ＮＬＯ稳定性也较好;在室温下放置９０天后,其ｄ３３值能维持初始值的９３．５％,在１００℃下放置３００ｍｉｎ后,其ｄ３３值仍能维持初始值的６０％。     

稀土β-二酮类配合物掺杂硅胶的光声光谱及荧光光谱研究

用Ｓｏｌ－Ｇｅｌ过程制备了一系列稀土β－二酮类配合物掺杂的ＳｉＯ２凝胶，测量了这些掺杂ＳｉＯ２凝胶的光声光谱，与固体配合物相比，掺杂ＳｉＯ２凝胶的光声光谱吸收峰发生蓝移，荧光发射峰发生红移。从无辐射跃迁角度研究了掺杂凝胶的Ｅｕ－β二酮类配合物的分子内能量传递模型。     

Structure of TiO2 in TiO2-SiO2 prepared by a complexing agent-assisted sol-gel procedure

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.     

Interaction of colloidal TiO2 with bovine serum albumin: A fluorescence quenching study

The interaction between colloidal TiO₂ and bovine serum albumin (BSA) was studied by using absorption and fluorescence spectroscopic methods. The quenching of the intrinsic protein fluorescence in the presence of different concentrations of colloidal TiO₂ was analyzed and number of binding sites (n) and apparent binding constant (K) were measured. The quenching mechanism of albumin by colloidal TiO₂ is discussed. The energy transfer efficiency (E) and critical transfer distance (R₀) were determined.     

Formation of Anatase Nanocrystals in Sol-Gel Derived TiO2-SiO2 Thin Films with Hot Water Treatment

We have successfully prepared transparent and porous anatase nanocrystals-dispersed films by treating the sol-gel derived TiO₂-SiO₂ films containing poly(ethylene glycol), PEG, with hot water. This process was done at temperatures lower than 100°C under atmospheric pressure, and thus anatase nanocrystals-dispersed films can be formed on various kinds of substrates including organic polymers with poor heat resistance. The changes in structure and composition of the TiO₂-SiO₂ gel films with hot water treatment were related to the formation process of anatase nanocrystals in the TiO₂-SiO₂ gel films with hot water treatment. The formation of anatase nanocrystals was found to proceed to hydrolysis of Si–O–Ti bonds and dissolution of SiO₂ component. In addition, porous film structure formed by leaching of PEG with hot water treatment led to homogenous dispersion of anatase nonocrystals in the films.     

The Preparation and Characterization of La Doped TiO2 Nanotubes and Their Photocatalytic Activity

La-doped TiO₂ nanotubes (La/TiO₂ NTs) were prepared by the combination of sol-gel process with hydrothermal treatment. The prepared samples were characterized by using transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectra, and ultraviolet-visible spectra. The photocatalytic performance of La/TiO₂ NTs was studied by testing the degradation rate of methyl orange under ultraviolet (UV) irradiation. The results indicated La/TiO₂ NTs calcined at 300°C consisted of anatase as the unique phase. The absorption spectra of the La/TiO₂ NTs showed a stronger absorption in the UV range and a slight red shift in the band gap transition than that of pure TiO₂ nanotubes. The photocatalytic performance of TiO₂ NTs could be improved by the doping of lanthanum ions, which is ascribed to several beneficial effects the formation of Ti-O-La bond and charge imbalance, existing of oxygen defects and Ti³⁺ species, stronger absorption in the UV range and a slight red shift in the band gap transition, as well as higher equilibrium dark adsorption of methyl orange. 0.75 wt% La/TiO₂ NTs had the best catalytic activity.     

Photoinduced interactions between colloidal TiO2 nanoparticles and calf thymus-DNA

The interaction of colloidal TiO₂ nanoparticles with calf thymus-DNA was studied by using absorption, FT-IR, steady state and time resolved fluorescence spectroscopic techniques. The apparent association constant has been deduced (K_app = 2.85 × 10³ M⁻¹) from the absorption spectral changes of the DNA-colloidal TiO₂ nanoparticles using the Benesi–Hildebrand equation. Addition of colloidal TiO₂ nanoparticles quenched the fluorescence of EtBr–DNA. The number of binding sites (n = 0.97) and the apparent binding constant (K = 6.68 × 10³ M⁻¹) were calculated from relevant fluorescence quenching data. The quenching, through a static mechanism, was confirmed by time resolved fluorescence spectroscopy.     

Centrally Coordinated Cobalt Porphyrin Monolayers on the Surface of TiO2 Nanoparticles

Aminopropyltrimethoxysilane (APTS) on the surface of TiO₂ nanoparticles was used to bind cobalt(II) 5,10,15,20-tetra-(4-trimethylaminophenyl)porphyrin iodide (CoTAPPI). The binding involved coordination of amino-group in the APTS to cobalt(II) ion in the center of the porphyrin. The absorption and fluorescence spectra of the products showed that there existed the electron transfer among TiO₂, APTS, and CoTAPPI. The polarized fluorescence spectra were used to evaluate the coordination constants of the porphyrin and APTS. The molecular geometry and binding energy of the TiO₂-APTS-CoTAPPI assembly were calculated with the molecular mechanics approach (MM2).     

Preparation of Au-TiO2 Hybrid Nano Particles in Silicate Film Made by Sol-Gel Method

TiO₂ nano particles with photo catalytic property were mixed with silica alkoxides solution with HAuCl₄/4H₂O. STS02 (purchased from Ishihara Sangyo Kaisha, Ltd.) was used as TiO₂ nano particles. The average size of TiO₂ nano particles was 7 nm in diameter. The gel film coated on glass substrate was heated and then HAuCl₄/4H₂O was thermally reduced at 390 degree. The coated silica gel film doped with HAuCl₄/4H₂O and TiO₂ nano particles was turned into light blue from colorless gel film after heat treatment. The optical absorption spectrum showed the absorption peak of the film heated at 390 degree shifted to at about 650 nm compare to SiO₂ film doped with Au nano particles without TiO₂ nano particles that had absorption peak at 542 nm. On the other hand, the film formed from coating solution incorporated TiAA (titanium tetraisopropoxide chelated by acetyl acetone) as TiO₂ source instead of TiO₂ nano particles had absorption peak at 550 nm. That means there was no effect on formation of Au nano particles when TiAA was incorporated. The average size of the particles was found to be about 23 nm in diameter by TEM observation. Furthermore EDX (Energy Dispersive X-ray Fluorescence Spectrometer) analysis of nano particles in the film indicated that Au-TiO₂ nano hybrid particles were formed. Simulation results also supported that the size in diameter of Au nano particles had little influence on the absorption coefficient of the silica film doped with Au nano particles.     

静电自组装制备纳米TiO2/SiO2光催化材料

采用静电自组装方法制备了纳米TiO2/SiO2光催化材料。采用巯丙基三甲氧基硅烷偶联剂对SiO2进行干法改性,采用双氧水/冰醋酸将偶联剂巯基基团氧化为磺酸基基团。在正负电荷的吸引下,带负电荷的SiO2与带正电荷的钛聚合阳离子自发地组装在一起,经一定温度热处理得到纳米TiO2/SiO2光催化材料。采用XRD、FTIR、PL、UV-Vis DRS、SEM和ICP等对材料进行了分析和表征。采用甲基橙溶液评价材料的光催化性能。结果表明:SiO2促使锐钛矿的形成,抑制锐钛矿向金红石的转变,减小TiO2的晶粒尺寸,使得TiO2光吸收波长发生蓝移。TiO2与SiO2通过Si-O-Ti键发生结合。采用静电自组装方法制备的材料中TiO2的含量高于传统方法,导致材料的光催化性能有所提高。     

香豆素343敏化TiO2纳米粒子光致电子转移的荧光和拉曼光谱

通过对香豆素343(C343)染料敏化TiO₂纳米粒子光致电子转移的荧光和拉曼光谱特性的研究表明,C343染料敏化TiO₂纳米粒子稳态吸收光谱和稳态荧光光谱的红移归因于从被吸附的C343染料分子激发态和C343/TiO₂复合物到TiO₂纳米粒子导带的光致电子转移. 由时间分辨荧光光谱确定了C343染料敏化TiO₂纳米粒子的逆向电子转移速率常数为τ₁=31 ps. C343 染料敏化TiO₂纳米粒子体系拉曼光谱的研究表明, 被吸附在界面处的染料分子主链碳键的伸缩振动和碳环的呼吸运动的振动模式对超快界面光致电子转移有着重要的促进作用.     

Bactericidal performance of photocatalytic titanium dioxide particle mixture under ultraviolet and fluorescent light: an in vitro study

When ultraviolet (UV) light comes into contact with titanium dioxide (TiO₂), a variety of free radicals are released to provide a potent oxidizing power. Few reports are available, however, evaluating the bactericidal effects of TiO₂ particle under UV light and fluorescent light (FL) in the same line of research for clinical applications. In the present study, we set out to evaluate the in vitro photocatalytic bactericidal effects on Staphylococcus aureus, which is one of the most common pathogens of infectious disease, in an aqueous system of TiO₂ particles irradiated by UV and FL. A TiO₂ particle mixture containing 0.019 mg/ml of TiO₂ was prepared. A bacterial solution was added dropwise to the mixture, and the resulting product was irradiated by UV or FL light. The colony‐forming units were counted and the bacterial survival rate was calculated. Control samples maintained a relatively high bacterial survival rate. In the TiO₂ mixture group, however, the bacterial survival rate decreased steadily, reaching 9.4% after 60 min of exposure to UV light and 10.9% after 60 min of FL irradiation. Distributing the TiO₂ particles in a water mixture produces highly efficient light absorption and enables greater and more frequent adhesion with bacteria, allowing a high degree of photocatalytic antibacterial action. Although the quantity was inferior to UV, our TiO₂ particles were able to show effective bactericidal activity even under FL. The TiO₂ particle mixture is expected to prove effective in preventing postoperative infection. Copyright © 2009 John Wiley & Sons, Ltd.