含酰胺结构的巯基自组装膜的设计与结构表征

提出了一种简便通用的合成巯基化合物的途径，以分子中的羧基CO2H为起始基团，与2-流基乙胺的氨基选择性缩合；合成了一系列具有RC（O）NHCH2CH2SH（R分别为偶氯苯衍生物，双炔衍生物及直链烷基）结构的化合物，并用接触角测量，电化学和掠角反射红外光谱（GIR-IR）等手段对这些化合物在金表面形成的自组装单分子膜进行了表征。发现4-（N－（2‘-巯基已基））酰胺偶氮苯的自组装膜表现出良好的电活性，电化学测定表面浓度为4．21×10(－10)mol·cm(-2)．当R为烷基链时，随烷基链的增长，膜的致密度与有序度增加GIR-IR证明在自组装腹中CH3（CH2）6C（O）NHCH2CH2SH的C＝O和N－H键与Au表面平行，分子轴线与Au表面近似垂直．     

自组装成膜技术制备TiO2薄膜的XPS研究

采用自组装成膜技术制备里TiO2薄膜,应用X射线光电子能谱研究自组装膜及其氧化膜和淀积的TiO2薄膜，结果表明，硅烷偶联剂成功地组装在玻璃基片上，足够长时间的氧化对使端基（-SH）完全氧化为磺酸基，淀积在基片上的TiO2膜牢固性好，平均膜厚在10nm．淀积膜中的钛可能有几种不同的氧化态，不同的酸度影响TiO2的淀积效果     

SO_4~(2-)/Ce-TiO_2光催化降解二甲基二氯乙烯基磷酸酯

以钛酸四丁酯 (Ti(OBu) 4 )、Ce(NO3 ) 3 、H2 SO4为主要原料 ,采用溶胶 凝胶法制备了SO2 -4/Ce TiO2 光催化剂 ,用XRD、IR、BET、XPS、TG DTA等测定技术对所制得的试样进行了表征 ,并将其用于光催化降解二甲基二氯乙烯基磷酸酯的稀释液。结果表明 ,SO2 -4/Ce TiO2 中TiO2 以锐钛矿晶型存在 ,并且具有超强酸特征 ,当n(Ce) /n(TiO2 ) =0 0 0 5 ,c(H2 SO4) =0 5mol/L时 ,焙烧温度为 5 0 0℃是最佳制备条件 ,其光催化降解性能较Ce TiO2 有明显提高。     

疏基烷氧基喹啉化合物的合成

自组装单分子膜 ( Self- Assembled Monolayer,SAM)由于其致密和高度有序性在分子器件、修饰电极、纳米电子学以及仿生科学等领域有着广泛的应用前景。可用于自组装的材料有脂肪醇、有机硅烷和烷基硫醇类衍生物 [1]。自组装膜的研究大多数集中于巯基化合物在金表面共价吸附形成的单分子膜 ,为了得到具有不同功能的自组装膜就需要合成带有不同功能基团的巯基化合物。广泛使用的是具有X( CH2 ) n SH结构的巯基化合物 [2 ] ( X为所感兴趣的官能团 )。文献 [3] 报道了含酰胺键、偶氮苯基的 SAM材料的合成。巯基烷氧基喹啉化合物是一类新型…     

制备失水山梨醇单油酸酯的选择性酯化反应研究

研究了几种酸性催化剂(H2SO4、H3PO4、CH3C6H4SO3H)、碱性催化剂(NaOH、Na2CO3、NaHCO3)和氧化物(ZnO、Al2O3、TiO2)对山梨醇和油酸的催化酯化反应.结果表明用酸性催化剂催化的酯化反应产品中的双油酸酯的比例较高;用碱性催化剂或氧化物催化剂催化的酯化反应产品中的单油酸酯的比例较高,其中用ZnO催化所得产品中的单油酸酯的比例可达91%.     

甲硫醇定向合成催化剂活性相研究进展

甲硫醇(CH3SH)是医药、农药、饲料和合成材料等领域的重要有机合成中间体,以硫化氢合成气(CO/H2/H2S)一步催化合成CH3SH具有广泛的应用前景.目前,钾改性的二硫化钼材料是一步法合成CH3SH最高效和广泛的催化剂,但是对催化剂活性相以及K和MoS2之间物理化学行为认知的不足严重限制了其催化性能.我们主要综述了...     

有机钛化学III.1,5-环辛二烯的钛催化均相氢化

本文研究了一系列有机钛化合物(R-C5H4)2TiCl2(R=H,CH3,C2H5,n-C3H7,CH2-CHCH2.CH3CH-CHCH2.CH3OCH2CH2,C2H5OCH2CH2,cyclo-C6H1)等)和还原剂((i-Bu)3Al,LiAlH4,i-C3H7MgBr)组成的低价钛催化体系对1,5-环辛二烯的均相催化氢化反应。结果表明,低价钛催化体系在温和条件下具有较好的催化活性,氢化时还同时发生异构化反应,并讨论茂环上取代基对反应的影响及催化机理。     

有机染料罗丹明B在复合催化剂TiO2-APS-PW11Ni作用下的光降解研究

利用自组装方式制备了多酸-有机胺-二氧化钛复合催化剂K5Ni(H2O)PW11O39-APS-TiO2(APS为(C2H5O)3SiCH2CH2CH2NH2的简称),简称为TiO2-APS-PW11Ni,通过红外(IR),紫外漫反射(UV/DRS)对其组成和结构进行了表征.并利用该催化剂光降解染料污染物罗丹明B(RB)水溶液,与纳米TiO2催化剂光降解进行对比,结果表明,染料罗丹明B在复合催化剂作用下的催化效果明显优于TiO2光催化效果,计算得降解半衰期分别为:T1/2(复合催化剂)＝6.5 min,T1/2(TiO2)＝21.2 min.     

三维有序大孔杂化材料3DOM PW11Ni-APS-TiO2紫外光催化降解罗丹明B

采用甲醇法制备三维有序大孔结构(3DOM)TiO2,再经过有机胺(EtO)3Si(CH2)3NH2(APS)功能化修饰后,通过自组装技术将取代型杂多酸盐K5[Ni(H2O)PW11O39](PW11Ni)与其负载,从而制备了三维有序大孔取代型多金属氧酸盐-有机胺-TiO2杂化催化剂3DOM PW11Ni-APS-TiO2。通过FT-IR,ICP-AES,XRD,UV-Vis/DRS, XPS和SEM等测试手段对其组成、结构和形貌等进行了表征,结果表明,通过自组装技术将APS功能化修饰的3DOM TiO2与杂多酸盐PW11Ni负载后,该杂多酸盐PW11Ni通过Ni-N配位键与3DOM TiO2键合。同时,所制备的3DOM PW11Ni-APS-TiO2具有TiO2锐钛矿结构,且该合成产物由于模板剂聚苯乙烯(PS)胶球的作用呈现着规则、有序和开放性的三维有序大孔结构,其通透性的孔结构十分有利于反应过程中反应物和产物分子的扩散。紫外光催化降解罗丹明B实验结果表明,3DOM PW11Ni-APS-TiO2的紫外光催化降解活性明显高于直接光解和其他对比体系。     

水溶液法制备图案化TiO2薄膜

从硫酸钛Ti(SO4)2的水溶液出发, 采用化学浴沉积和电沉积法来制备图案化TiO2薄膜. 通过硫酸和双氧水来稳定Ti4+, 配制了pH=1.0的硫酸钛溶液和pH=1.6的过氧硫酸钛溶液. 结合微接触印刷术在硅基底上制得自组装膜预图案, 再化学浴沉积TiO2即可得规则图纹. 无机配体对钛溶液的稳定性和TiO2的晶型均有影响, 溶液的酸度关系到所得图案的质量. 过氧硫酸钛溶液同样适用于电沉积, 在导电玻璃基底上旋涂光刻胶后选择性曝光、显影, 通过控制阴极电位可获得高差达200 nm的清晰图案.     

Photocatalytic patterning of monolayers for the site-selective deposition of quantum dots onto TiO2 surfaces

A novel photochemical mechanism is reported for the site-selective deposition of quantum dots onto nanocrystalline TiO2 films. The patterning mechanism involves the combination of surfactant-mediated self-assembly and monolayer photolithography. In the self-assembly process, CdS and CdSe quantum dots were attached to TiO2 surfaces through bifunctional mercaptoalkanoic acid (MAA) linkers. MAAs were adsorbed to the TiO2 surface as the deprotonated carboxylates, primarily through monodentate coordination to Ti4+ sites. CdSe quantum dots were bound to the terminal thiol groups of surface-adsorbed MAAs, with a surface adduct formation constant, Kad, of (2.1 +/- 0.7) x 104 M-1. The color and optical density of the quantum dot-functionalized TiO2 films were tunable. Monolayer photopatterning involved the TiO2-catalyzed oxidative degradation of surface-adsorbed mercaptohexadecanoic acid (MHDA). A mechanism is proposed wherein MHDA degradation occurs through both oxidative decarboxylation and the formation of interchain disulfides. These MHDA photodegradation processes regulate the extent to which CdSe quantum dots adsorb onto the TiO2 surface. Illumination through a photomask yielded optically patterned, quantum dot-functionalized TiO2 films that were characterized by scanning electron microscopy and energy-dispersive X-ray analysis.     

Antireflection and self-cleaning properties of a moth-eye-like surface coated with TiO2 particles

Poly(ethylene terephthalate) (PET) films with a moth-eye-like surface are coated with TiO(2) particles to form self-cleaning antireflective films. The use of a TiO(2) suspension of high concentration to coat the PET surface produces a thicker TiO(2) layer with smaller pores, whereas a low concentration of a TiO(2) suspension gives a thinner layer of TiO(2) with larger pores. The PET films coated with TiO(2) particles exhibit a high transmittance of 76-95% and almost no absorption in the range of 400-800 nm. The PET films coated with a TiO(2) suspension with a concentration of ≥2 vol % exhibit superhydrophilicity after irradiation with UV light. After irradiation, the superhydrophilic nature is retained for at least 18 days. The TiO(2)-coated PET films showed the ability to decompose methylene blue under UV irradiation.     

Rup_2P表面敏化TiO_2基复合薄膜光致界面电荷转移

采用离子束溅射技术制备出TiO2/ITO、Zn2+掺杂的TiO2(TiO2-Zn)/ITO和TiO2/ZnO/ITO薄膜,采用表面敏化技术和旋转涂膜法,制备出(1,10-邻菲咯啉)2-2-(2-吡啶基)苯咪唑钌混配配合物(Rup2P)表面敏化的TiO2基复合薄膜Rup2P/TiO2/ITO、Rup2P/TiO2-Zn/ITO和Rup2P/TiO2/ZnO/ITO.表面光电压谱(SPS)结果发现:敏化后的TiO2基薄膜在可见区(400-600nm)产生SPS响应;TiO2基薄膜的能带结构不同,其在400-600nm和350nm处的SPS响应的峰高比不同.利用电场诱导表面光电压谱(EFISPS),测定TiO2基薄膜和表面敏化TiO2基复合薄膜各种物理参数,并确定其能带结构.分析可知,表面敏化TiO2基复合薄膜在400-600nm的SPS响应峰主要源于Rup2P分子的中心离子Ru4d能级到配体1,10-邻菲咯啉π*1和2-(2-吡啶基)苯咪唑π*2能级的跃迁;TiO2中Zn2+掺杂能级有利于Ru4d能级到配体π*1和π*2跃迁的光生电子向TiO2-Zn导带的注入;TiO2/ZnO异质结构有利于光生电子向ITO表面的转移,从而导致可见光(400-600nm)SPS响应增强以及光电转换效率的提高.     

Adsorption and solar light decomposition of acetone on anatase TiO2 and niobium doped TiO2 thin films

Adsorption and solar light decomposition of acetone was studied on nanostructured anatase TiO2 and Nb-doped TiO2 films made by sol-gel methods (10 and 20 mol % NbO2.5). A detailed characterization of the film materials show that films contain only nanoparticles with the anatase modification with pentavalent Nb oxide dissolved into the anatase structure, which is interpreted as formation of substituted Nb=O clusters in the anatase lattice. The Nb-doped films displayed a slight yellow color and an enhanced the visible light absorption with a red-shift of the optical absorption edge from 394 nm for the pure TiO2 film to 411 nm for 20 mol % NbO2.5. In-situ Fourier transform infrared (FTIR) transmission spectroscopy shows that acetone adsorbs associatively with eta1-coordination to the surface cations on all films. On Nb-doped TiO2 films, the carbonyl bonding to the surface is stabilized, which is evidenced by a lowering of the nu(C=O) frequency by about 20 cm(-1) to 1672 cm(-1). Upon solar light illumination acetone is readily decomposed on TiO2, and stable surface coordinated intermediates are formed. The decomposition rate is an order of magnitude smaller on the Nb-doped films despite an enhanced visible light absorption in these materials. The quantum yield is determined to be 0.053, 0.004 and 0.002 for the pure, 10% Nb:TiO2, and 20%Nb:TiO2, respectively. Using an interplay between FTIR and DFT calculations we show that the key surface intermediates are bidentate bridged formate and carbonate, and H-bonded bicarbonate, respectively, whose concentration on the surface can be correlated with their heats of formation and bond strength to coordinatively unsaturated surface Ti and Nb atoms at the surface. The oxidation rate of these intermediates is substantially slower than the initial acetone decomposition rate, and limits the total oxidation rate at t>7 min on TiO2, while no decrease of the rate is observed on the Nb-doped films. The rate of degradation of key surface intermediates is different on pure TiO2 and Nb-doped TiO2, but cannot explain the overall lower total oxidation rate for the Nb-doped films. Instead the inferior photocatalytic activity in Nb-doped TiO2 is attributed to an enhanced electron-hole pair recombination rate due to Nb=O cluster and cation vacancy formation.     

不同基材上TiO2膜的表征和光催化活性评价

 采用溶胶-凝胶法在平行条件下制备了负载于钛、铝、不锈钢和玻璃等不同基材上的TiO2浸渍提拉膜,利用原子力显微镜、俄歇电子能谱、X射线衍射、漫反射紫外-可见光谱和苯甲酰胺光催化降解等手段对TiO2膜进行了表征和催化活性评价. 实验结果表明,基材的种类对TiO2膜的性能有较大影响,各膜样品虽均为锐钛矿晶型,但表面形貌显著不同. TiO2/Ti, TiO2/steel, TiO2/Al和TiO2/glass上TiO2的平均粒径分别是152, 205, 241和477 nm,且前两者的粒径分布较为集中. TiO2/Ti和TiO2/Al样品表面仅有Ti和O元素存在,而TiO2/steel和TiO2/glass表面则分别检测到有Fe和Na,Ca及Si等基材元素渗出. 各膜样品对苯甲酰胺光催化降解的活性次序是:TiO2/Ti＞TiO2/Al＞TiO2/glass＞TiO2/steel. 根据实验结果可以推测,在焙烧阶段各基材上前驱体膜烧结行为的不同以及基材元素的渗出是造成不同基材上的TiO2膜在表面形貌、化学组成、光吸收性能以及光催化活性方面存在明显差异的主要原因.     

TiO2 surface modification and characterization with nanosized PbS in dye-sensitized solar cells

The nanoporous TiO2 films utilized in dye-sensitized solar cells (DSSCs) possess a large surface-to-volume ratio, which facilitates the adsorption of sensitizing dye and the recombination due to the high density of surface traps. In this paper, nanosized PbS was fabricated on the TiO2 films. The components of the modified TiO2 film were studied by X-ray diffraction (XRD) and electron probe microanalysis (EPMA), while the structure of the film was characterized with BET physisorption and high-resolution scanning electron microscopy (HRSEM). The results showed that the PbS particles were 2-3 nm and discrete on the surface of TiO2. Diffusion photovoltage (PV) spectroscopy was employed to study the charge separation and diffusion processes inside modified and unmodified TiO2 films. The diffusion PV signals revealed that the traps on the surface of TiO2 were extremely reduced due to the presence of PbS. The results of transient photovoltage and back I-V characteristics showed that the back reaction, that is, the recombination due to the reaction between an electron on TiO2 and the hole-transporting media, was retarded significantly.     

BPA对低温制备锐钛矿型TiO2薄膜表面形貌的控制

采用4,4’-二羟基二苯基丙烷(BPA)作为TiO2薄膜表面形貌控制的模板剂. 将BPA的乙醇溶液与具有锐钛矿晶粒的TiO2溶胶均匀混合制得涂膜液, 采用浸渍提拉法制备薄膜; 用无水乙醇将薄膜中的BPA选择性溶解去除, 实现了低温下锐钛矿型TiO2薄膜的制备及其表面形貌的调控. 采用SEM考察了TiO2溶胶用量、BPA用量、以及无水乙醇用量等因素对TiO2薄膜表面形貌的影响, 并对其控制机理进行了探讨. 结果表明, 涂膜液的组成会影响到湿膜烘干过程中粒子的迁移和聚集, 从而改变TiO2与BPA 在薄膜表面的分布状态, 最终对TiO2薄膜的表面形貌产生影响. 随BPA浓度的降低,其影响逐渐由薄膜内部转向薄膜的表面区域. 而低TiO2胶粒浓度和高乙醇含量则有利于TiO2薄膜产生粗糙的形貌或多孔性的结构.     

Synthesis of biomorphological mesoporous TiO2 templated by mimicking bamboo membrane in supercritical CO2

A new approach is presented for preparing biomorphological mesoporous TiO2 templated by mimicking bamboo inner shell membrane via supercritical CO2 (SCCO2) transportation through titanium tetrabutyloxide (TTBO). The analysis of wide-angle X-ray powder diffraction (XRD) showed the prepared TiO2 in phase of anatase, and the small-angle XRD revealed the presence of mesopores without periodicity. The product exhibited the shape of crinkled films and extended in two dimensions up to centimeters. The electron microscopic observation showed that the TiO2 films were around 200 nm in thickness, and across the films there were numerous round or ellipse-shaped mesopores, being 10-50 nm in diameter, which were formed by the close packing of TiO2 particles. High-resolution transmission electron microscope (HRTEM) displayed that the single TiO2 particle size was about 12.5 nm. The UV-vis absorption spectrum was transparent in the wavelength of 320-350 nm for suspensions of the prepared mesoporous TiO2 in ethanol at the concentration of 5.0 mg/l. The mesoporous TiO2 prepared with the aid of SCCO2 exhibited an obvious blue shift compared with the TiO2 prepared by sol-gel infiltration. The possible mechanism for the formation of the mesoporous TiO2 is summarized into a biomimetic mineralization pathway. First, TTBO was transported to the membrane surface via SCCO2, and then condensed. Hydrolysis reactions between the functional groups of organic membrane and TTBO took place to form the nuclear TiO2, and the TiO2 seeds grew around the organic membrane into TiO2 mesoporous materials. The approach provides a low-cost and efficient route for the production of ceramics nanomaterials with unique structural features, which may have potential application in designing UV-selective shielding devices [S. Zhao, X.H. Wang, S.B. Xin, Q. Jiang, X.P. Liang, Rare Metal Mater. Eng. 35 (2006) 508-510].     

Femtosecond fluorescence dynamics of porphyrin in solution and solid films: the effects of aggregation and interfacial electron transfer between porphyrin and TiO2

The excited-state relaxation dynamics of a synthetic porphyrin, ZnCAPEBPP, in solution, coated on a glass substrate as solid films, mixed with PMMA and coated on a glass substrate as solid films, and sensitized on nanocrystalline TiO2 films were investigated by using femtosecond fluorescence up-conversion spectroscopy with excitation in the Soret band, S2. We found that the S2--> S1 electronic relaxation of ZnCAPEBPP in solution and on PMMA films occurs in 910 and 690 fs, respectively, but it becomes extremely rapid, <100 fs, in solid films and TiO2 films due to formation of porphyrin aggregates. When probed in the S1 state of porphyrin, the fluorescence transients of the solid films show a biphasic kinetic feature with the rapid and slow components decaying in 1.9-2.4 and 19-26 ps, respectively. The transients in ZnCAPEBPP/TiO2 films also feature two relaxation processes but they occur on different time scales, 100-300 fs and 0.8-4.1 ps, and contain a small offset. According to the variation of relaxation period as a function of molecular density on a TiO2 surface, we assigned the femtosecond component of the TiO2 films as due to indirect interfacial electron transfer through a phenylethynyl bridge attached to one of four meso positions of the porphyrin ring, and the picosecond component arising from intermolecular energy transfer among porphyrins. The observed variation of aggregate-induced relaxation periods between solid and TiO2 films is due mainly to aggregation of two types: J-type aggregation is dominant in the former case whereas H-type aggregation prevails in the latter case.     

光催化活性TiO2薄膜的低温制备

在低温下,将基材浸渍在含配合物,F－离子捕获剂H3BO3,及加有结晶诱导剂锐钛矿TiO2纳米晶的过饱和水溶液中,在基材上沉积锐钛矿型TiO2薄膜.研究了水溶液的浓度、反应物和H3BO3的摩尔比、沉积时间、反应温度等对沉积TiO2薄膜的结构和性能的影响.并用UV Vis、XRD和SEM等对TiO2薄膜的透明性、厚度、物相和形貌等进行了表征.用亚甲蓝的光催化降解,评价了TiO2薄膜的光催化活性.