溶胶-凝胶法制备改性TiO2纳米薄膜及其防腐蚀性能

应用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面分别制备TiO2纳米膜和 B-Fe-Ce改性的TiO2纳米膜. 采用场发射扫描电子显微镜(FE-SEM)、原子力显微镜(AFM)、拉曼光谱法和能量分散谱(EDS)对薄膜进行表征,通过电化学阻抗谱(EIS)和动电位阳极极化曲线的测试考察薄膜的耐蚀性及对不锈钢的保护性能. 结果表明:两种纳米薄膜均含锐钛矿型的TiO2纳米颗粒,纯TiO2纳米膜与改性后的纳米膜中颗粒直径分别约为15和10 nm. TiO2/316L不锈钢和 B-Fe-Ce-TiO2/316L不锈钢膜电极浸泡在0.5 mo.lL-1 NaCl溶液后,后者的电化学反应电阻较大,动电位阳极极化曲线的稳定钝化区较宽,击穿电位更高,说明改性的纳米膜的耐蚀性及其保护性能更好.     

纳米Na_2SiF_6的电化学制备、表征与荧光性质

采用溶胶-凝胶法在Ti表面修饰一层纳米TiO2(nanoTiO2)膜,经X射线粉末衍射(XRD)和扫描电镜(SEM)表征,证明多孔TiO2膜的平均孔径为80 nm.以该多孔膜电极为模板,借助电化学沉积的方法制备了纳米Na2SiF6(nano Na2SiF6).经XRD和透射电镜(TEM)测试证实该Na2SiF6为均一的白锰钒型结构,平均粒径约为20 nm.初步研究了其荧光性质,发现在452.4 nm和285 nm处分别有强的荧光发射峰和激发峰.     

N掺杂TiO2纳米膜吸附胆红素分子的石英晶体微天平研究

以柠檬酸催化溶胶-凝胶法合成了晶粒尺寸为16.9 nm的锐钛矿型N掺杂TiO2(N-TiO2)纳米颗粒,并用旋转涂膜法制备了N-TiO2纳米薄膜.采用石英晶体微天平(QCM)技术研究了胆红素在纳米N-TiO2膜表面的吸附动力学行为,考察了缓冲溶液pH、硅烷亲脂试剂三甲基氯硅烷及金属离子修饰纳米N-TiO2膜对胆红素吸附...     

纳米TiO_2改性蚕丝丝素蛋白膜的研究

用溶胶凝胶法制备纳米TiO2改性再生蚕丝丝素蛋白膜.该丝素膜机械强度提高,在水中溶失率下降.UV、AFM、SEM测试的结果表明,丝素中纳米TiO2粒径约为80 nm,纳米粒子在丝素膜中分布均匀;XRD、FTIR测试结果表明,纳米TiO2的加入,可使改性丝素膜的结晶结构从SilkⅠ向SilkⅡ转化,其结晶度也随之提高;TGA测试表明改性丝素膜的热转变温度比纯丝素膜有所改变.     

同轴静电纺丝法在纳米中空Ti02纤维中填充Ag的应用

以聚乙烯吡咯烷酮(PVP)溶胶,钛酸四正丁酯和PVP溶胶,银颗粒为前驱体,以共轴静电纺丝法制备了银填充的TiO2中空纳米纤维.将双组分纤维在200℃下热处理去除乙醇与表面吸附水后,继而在空气气氛中焙烧至600℃.可以得到在内表面上沉积银颗粒的TiO2纳米管,银颗粒的直径为5-40 nm,TiO2纳米管的外径150-300 nm.管臂厚10-20 nm.用红外吸收光谱(IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试手段对超细纤维进行了表征.中空纤维的直径和管壁可以通过改变电纺参数来调节.与Ag-TiO2纳米纤维、TiO2纳米中空纤维、TiO2纳米纤维及TiO2纳米粉体相比较,Ag颗粒填充的TiO2纳米中空纤维在光分解亚甲基蓝上表现出了更好的光催化性能.     

同轴静电纺丝法在纳米中空TiO2纤维中填充Ag的应用

以聚乙烯吡咯烷酮(PVP)溶胶/钛酸四正丁酯和PVP溶胶/银颗粒为前驱体, 以共轴静电纺丝法制备了银填充的TiO2中空纳米纤维. 将双组分纤维在200 ℃下热处理去除乙醇与表面吸附水后, 继而在空气气氛中焙烧至600 ℃, 可以得到在内表面上沉积银颗粒的TiO2纳米管, 银颗粒的直径为5-40 nm, TiO2纳米管的外径150-300 nm, 管臂厚10-20 nm. 用红外吸收光谱(IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试手段对超细纤维进行了表征. 中空纤维的直径和管壁可以通过改变电纺参数来调节. 与Ag-TiO2纳米纤维、TiO2纳米中空纤维、TiO2纳米纤维及TiO2纳米粉体相比较, Ag颗粒填充的TiO2纳米中空纤维在光分解亚甲基蓝上表现出了更好的光催化性能.     

WC/TiO2纳米复合材料的制备及其电催化性能

以TiCl4为原料, 采用溶胶水解法合成了金红石型纳米TiO2颗粒, 并以其为载体制备了WC/TiO2纳米复合材料. 采用X射线衍射(XRD)、扫描电子显微镜(SEM)和X射线能谱(EDS)等手段分析了WC/TiO2纳米复合材料的晶相组成和表面形貌. 结果显示样品是由WC, TiO2和W组成, 纳米WC颗粒均匀地包覆在TiO2的表面, 并与TiO2构成了WC/TiO2纳米复合材料. 采用循环伏安法和计时电流法研究了WC/TiO2纳米复合材料对硝基苯的电催化性能. 结果表明, WC/TiO2纳米复合材料对硝基苯的电催化活性和电化学稳定性均优于介孔结构碳化钨(meso-WC)和纳米WC颗粒(part-WC).     

纳米TiO_2膜修饰电极异相电催化还原马来酸

通过电化学合成前驱体和溶胶 -凝胶法在Ti表面修饰一层纳米TiO2 膜 ,SEM ,XRD测试表明晶型为锐钛矿型 ,晶粒平均尺寸为 2 5nm .采用循环伏安法、循环方波伏安法和电解合成法研究了纳米TiO2 膜电极在硫酸介质中的氧化还原行为以及对马来酸 (maleicacid)还原的电催化活性 .结果表明 ,纳米TiO2 膜电极在阴极扫描时有两对可逆氧化还原峰 ,可逆半波电位Er1/ 2 分别为 -0 .5 3V和 -0 .92V (vs .SCE ,扫描速度 0 .0 5V·s-1) ,对应于TiO2 /Ti2 O3 和TiO2 /Ti(OH) 3 两个氧化还原电对的可逆电极过程 .其中TiO2 /Ti2 O3 电对对马来酸具有异相电催化还原活性 ,纳米TiO2 膜中的TiⅣ/TiⅢ 氧化还原电对作为媒质间接电还原马来酸为丁二酸 (butanediacid) ,反应机理为电化学偶联随后化学催化反应 (EC′)机理 .     

模板-电泳沉积法制备TiO2纳米棒

室温(约25℃)下,将钛酸四丁酯水解制得TiO2溶胶,利用电泳沉积法在氧化铝模板中填充胶体,经450℃煅烧处理,制备了TiO2纳米棒.用透射电子显微镜和X射线衍射仪对样品进行了表征.结果表明,所得到的TiO2纳米棒表面光滑、致密,直径约180 nm,具有锐钛矿型结构.     

TiO2纳米膜表面结构形态特征

采用反胶束法制备TiO2纳米溶胶,用浸渍提拉法在不同的条件下制备了三种TiO2多孔纳米薄膜,并利用AFM、SEM、XRD等方法对膜表面结构物理化学特性进行表征.结果表明三种膜基本上由粒径约为59 nm的纳米粒子以不同的方式堆积而成,溶胶刚生成时浸提一次,干燥、焙烧得到膜上纳米粒子分布均匀,所生成的二次粒子粒径最小,二次粒子形成的二次表面粗糙度最小,浸提10次得到膜上纳米粒子间存在较丰富缝隙结构,二次粒子粒径及其形成的表面粗糙度较大,而溶胶制备好陈化6 h后浸提得到的膜上二次粒子粒径最大,表面粗糙度最高.由分形理论估算得到三种膜的分形维数分别是2.22、2.20和2.27. XRD测试表明,膜上TiO2为锐钛矿晶相.这些结果表明,采用不同制备步骤得到的膜,其表面结构形态存在较大的差异.     

TiO_2/316L不锈钢薄膜电极在NaCl溶液中的耐腐蚀性能

应用sol gel法和提拉技术于 316L不锈钢表面构筑纳米TiO2薄膜,再经水热后处理以消除膜中的细小龟裂.SEM和XRD技术表征膜的形貌和厚度,线性极化法分别考察膜厚度、pH、和Cl浓度对纳米膜电极耐腐蚀性能影响.电化学交流阻抗检测纳米TiO2膜在 0. 5mol/LNaCl溶液中的阻抗随浸泡时间的变化,光电子能谱技术测定了经浸泡 1008h后的纳米膜中各元素相对百分含量和价态.结果表明:在中性或碱性条件下,厚度为 375~464nm的纳米膜其耐腐蚀性随浸泡时间的延长呈现初期增加而后稳定,浸泡 48h后腐蚀电流较之浸泡初期降低 2个数量级,耐腐蚀电阻增加 2个数量级,在浸泡 1 008h内没有发现腐蚀的产物,Fe是以原子态扩散到膜中.     

Effect of hydrophobicity on the stability of sol–gel silica coatings in vacuum and their laser damage threshold

Silica antireflective coatings modified by hexamethyldisilazane (HMDS) were deposited on clean substrates (silicon wafer or K9 glass blanks) by sol–gel processing. The effects of HMDS on the contamination resistant capability and laser-induced damage threshold (LIDT) of coatings were investigated. Transmission electron microscopy revealed that a stable sol with uniformly distributed silica particles with an average particle size of about 15 nm was acquired by adding appropriate amount of HMDS into the standard SiO₂ sol. With the modified sol the resultant coatings were hydrophobic and the contact angle for water increased with increasing amount of HMDS in the reaction mixture. Such increase in hydrophobicity was not the result of surface roughness. The antireflective properties were retained after HMDS-treatment and the maximum transmission values were above 99 %. The introduction of HMDS into silica sols had also increased the LIDT of coatings from 24.3 to 37.0 J cm^?2 when the molar ratio of HMDS to tetraethoxysilane was 0.05:1. The increase in LIDT was attributed to the decrease of nodular defect and uniform microstructures of coatings as an effect of the HMDS modification. After some of the hydroxyl groups on the surface of the SiO₂ particle were replaced by methyl groups, from which the SiO₂ particle gained a water-repellent surface, the stability of coatings in vacuum was increased. The maximum transmission values of modified coatings decreased by only 0.25 % after storage under vacuum for 168 h. In contrast, the standard sol–gel silica coatings decreased about 2 % under similar conditions. The LIDT of modified coatings remained as high as 30.8 J cm^?2, more than that of standard coatings stored for the same duration in air.     

TiO_2-K_2SiO_3无机涂层对空间材料Ag的防护行为研究

在微波电离型原子氮（AO）源地面模拟设备中对空间材料Ag及TiO_2- K_2SiO_3无机涂层进行原子氧剥蚀效应试验。用扫描电镜（SEM）、光电子能谱（ XPS）、红外光谱（FT-IR）、X射线衍射光谱（XRD）和LAMBDA-9分光光度计，对在 模拟原子氧（AO）环境中Ag及在其表面涂覆的无机涂层，所发生的侵蚀与防护作用 进行了表征研究。AO对Ag表现了较严重的侵蚀作用，原来光亮如镜的表面形貌变得 粗糙，且失去光泽。而所施用的TiO_2-K_2SiO_3无机涂层，经AO辐照后，表面形貌 则变化甚少。实验表明，该涂层对AO辐照有较强的防护效果、较好的空间稳定性（ AO辐照前后Δα ≈ 0.024），能阻止AO对基材的侵蚀。     

TiO_2-K_2SiO_3无机涂层对空间材料Ag的防护行为研究

在微波电离型原子氧 (AO)源地面模拟设备中对空间材料Ag及TiO2 K2 SiO3 无机涂层进行原子氧剥蚀效应试验 .用扫描电镜 (SEM)、光电子能谱 (XPS)、红外光谱 (FT IR)、X射线衍射光谱 (XRD)和LAMBDA 9分光光度计 ,对在模拟原子氧(AO)环境中Ag及在其表面涂覆的无机涂层 ,所发生的侵蚀与防护作用进行了表征研究 .AO对Ag表现了较严重的侵蚀作用 ,原来光亮如镜的表面形貌变得粗糙 ,且失去光泽 .而所施用的TiO2 K2 SiO3 无机涂层 ,经AO辐照后 ,表面形貌则变化甚少 .实验表明 ,该涂层对AO辐照有较强的防护效果、较好的空间稳定性 (AO辐照前后Δαs≈ 0 .0 2 4) ,能阻止AO对基材的侵蚀 .     

Effects of aging time on V2O5 sol-gel coatings

Vanadium pentoxide (V₂O₅) sols have been used in conductive coatings and related applications [1, 2, 3]; however, the changes which may occur in the properties of these coatings with sols of different ages have not been carefully shown. Properties which may be dependent on the age of the sol (sol viscosity, film morphology and conductance) were measured in this work. The coating sols were prepared by ion-exchange of sodium metavanadate solutions.It was found that the coating thickness, sol viscosity, and surface morphology of the coatings were directly related to the age of the sol used. The dried coating thickness increased from 3 microns to 20 microns over a 30 day period. The sol viscosity increased from 1 centipoise to near 2 centipoise. The surface morphology of the coatings changed from that of a featureless surface at day 1 to a continual coverage of micron-sized fibers as the coating sols aged. The conductivity of the coatings, though, was unaffected by the age of the sol. The coating properties were correlated to the amount of polymerization of dissolved precursors in solution.     

双金属核壳结构负载型Au@Ag/TiO2催化剂的制备及表征

利用溶胶法制备了Au核Ag壳(Au@Ag)结构复合纳米粒子,用粉末-溶胶法和水热合成法使其负载于TiO₂纳米粒子上,利用紫外-可见吸收光谱﹑X射线粉末衍射﹑透射电子显微镜对复合结构材料进行了结构表征,并对其光催化消除臭氧的性能进行了研究。结果表明,制备方法、Au/Ag化学计量比及金属负载量等对光催化消除臭氧的活性均有很大影响。采用粉末-溶胶法制备的1%-Au@Ag/TiO₂(n_Au/n_Ag=1∶3)催化剂,由于TiO₂表面沉积的Au@Ag金属颗粒尺寸小且分散度高,而且1%的金属担载量有利于光生电子空穴的有效分离,光催化消除臭氧的活性最高。     

TiO2-Al2O3复合氧化物负载NiMo加氢脱硫催化剂的研究

采用溶胶凝胶技术，从Al2O3载体的表面改性出发，制备了TiO2-Al2O3复合载体。采用此改性载体制备了NiMo／TiO2-Al2O3催化剂；用中压固定床微反装置考察了载体改性对制备的催化剂的噻吩加氢脱硫(HDS)活性的影响．用透射电镜、NH3-TPD及吡啶红外光谱法对改性载体和催化剂进行了表征．结果表明，经钛溶胶改性的载体制备的催化剂与原有载体制备的催化剂相比，催化剂活性提高了20％．改性载体表面负载的钛溶胶以纳米尺寸的TiO2微粒形态存在．     

电纺丝-气相沉积法制备碳包覆TiO_2纳米纤维及其光催化行为的研究

以聚乙烯吡咯烷酮(PVP)溶胶/钛酸正丁酯为前躯体,以静电纺丝法制备了PVP/Ti(OC4H9)4纤维。550℃下,空气氛中焙烧双组分纤维,得到直径60～300nm的TiO2纳米纤维。继而以气相沉积法制得碳包覆TiO2纳米纤维。用红外吸收光谱(FTIR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等对纳米纤维进行了表征。与TiO2纳米纤维、TiO2纳米粉体相比,气相沉积法制备的碳包覆TiO2纳米纤维在光分解亚甲基蓝上表现出更好的催化性能。     

Synthesis of Chemically Asymmetric Silica Nanobottles and Their Application for Cargo Loading and as Nanoreactors and Nanomotors

We report the synthesis of chemically asymmetric silica nanobottles (NBs) with a hydrophobic exterior surface (capped with 3‐chloropropyl groups) and a hydrophilic interior surface for spatially selective cargo loading, and for application as nanoreactors and nanomotors. The silica NBs, which have a “flask bottle” shape with an average diameter of 350 nm and an opening of ca. 100 nm, are prepared by anisotropic sol–gel growth in a water/n‐pentanol emulsion. Due to their chemically asymmetric properties, nanoparticles (NPs) with hydrophilic or hydrophobic surface properties can be selectively loaded inside the NBs or on the outside of the NBs, respectively. A high‐performance nanomotor is constructed by selectively loading catalytically active hydrophilic Pt NPs inside the NBs. It is also demonstrated that these NBs can be used as vessels for various reactions, such as the in situ synthesis of Au NPs, and using Au NP‐loaded NBs as nanoreactors for catalytic reactions.