有机/纳米二氧化钛杂化材料的合成与表征

采用溶胶 -凝胶聚合法 ,制备了稳定的纳米二氧化钛 /有机聚合物改性的杂化材料。研究了不同的反应方法对该杂化材料的粒子形状、溶液稳定性和光折射率的影响。红外光谱和透射电镜分析表明 :该材料是由内部的Si -O -Ti键和表面有机聚合物组成的 ,并且有纳米尺寸的结构。该杂化材料在甲苯 /丁醇组成的混合溶剂中具有良好的稳定性     

新型PMMA/SiO_2/DR1非线性光学杂化材料的制备及表征

通过溶胶-凝胶法将硅烷染料DR1ASD、含硅氧烷PMMA和TEOS在酸催化条件下共水解-缩合制备了新型非线性光学杂化材料PMMA/SiO2/DR1,并运用FT-IR、SEM、UV-vis、DSC/TG和UV-vis等测试方法对其结构和性能进行表征.测试结果表明:杂化材料中有机相和无机相之间通过共价键结合,无相分离出现;杂化材料的玻璃化转变温度(Tg)和热分解温度(Td)分别达到165℃和405℃;电晕极化后杂化材料具有较高的生色团取向有序度(Φ=0.238),并表现出良好的取向稳定性,80℃条件下3h后依然有初始值的79%.     

Synthesis and characterization of TiO2 nanotube/hydroquinone hybrid structure

It is shown that 1,4-benzenediol (hydroquinone) and TiO2 nanotubes can form a hybrid structure that is stable in aqueous environment. The incorporation of hydroquinone restores the local structure of nanotubes to anatase-like as evidenced by Raman spectroscopy. Subtle overall structural changes take place upon annealing of the hybrid structure contributing to its stability. The hybrid system shows a broad optical absorption peak extending significantly beyond 700 nm with potential applications in photocatalysis and photoelectrochemistry.     

Synthesis and properties of a novel isomeric polyimide/SiO2 hybrid material

A novel isomeric polyimide/SiO₂ hybrid material was successfully prepared through sol–gel technique, and its structure, thermal properties and nano-indenter properties were investigated. First, 3-[(4-phenylethynyl)phthalimide]propyl triethoxysilane (PEIPTES) was successfully synthesized, its structure was characterized by elemental analysis, FT-IR and ¹³C NMR. The researches on solubility and thermal properties of PEIPTES show that it can be used for modifying nano-SiO₂ precursor. Nano-SiO₂ precursor was synthesized by tetraethoxysilane (TEOS) through sol–gel technique. Then the PEIPTES solution and the nano-SiO₂ precursor were mixed for 6 h to let the PEIPTES molecules react with the nano-SiO₂ precursor, and modified nano-SiO₂ precursor was obtained. The modified reaction was confirmed by the analyses of FT-IR. At last, isomeric polyimide/SiO₂ hybrid material was produced by using isomeric polyimide resin solution and the modified nano-SiO₂ precursor after heat treatment process. The structure analysis by SEM indicated that SiO₂ particles dispersed in isomeric polyimide matrix homogeneously with nanoscale. Thermogravimetric analyzer, dynamic mechanical thermal analyzer and nano-indenter XP was employed to detect the properties of the materials, the results demonstrated that isomeric polyimide/SiO₂ hybrid material has much better thermal properties and nano-indenter properties than those of isomeric polyimide. It is confirmed that PEIPTES acts as a bridge between the SiO₂ particles and the isomeric polyimide matrix in the hybrid material, because the ethoxyl of PEIPTES could participate in the hydrolyzation and condensation to form chemical bond with SiO₂ particles and its phenylethynyl group could take part in the cross-curing reaction of isomeric polyimide.     

Synthesis of mesostructured TiO2-based material and its functionalization with silver nanoparticles

We report the results of a template synthesis of a three-dimensional nanostructured material based on titanium(IV) oxide modified with silver nanoparticles. The chemical composition and structure of the material have been determined by scanning electron microscopy, IR spectroscopy, and X-ray diffraction.     

新型药物载体材料——端羟基聚(丙交酯-co-对二氧环己酮)的合成与表征

聚乳酸(PLA)作为药物载体材料存在因疏水性强而导致的药物释放速率难控以及在循环系统中停留时间短等问题.研究表明,在PLA中引入乙醇酸(GA)可提高材料降解速率,引入聚乙二醇(PEG)则可延长共聚物在循环系统中的停留时间.研究以丙交酯(LA)和对二氧环己酮(PDO)为主要原料,在辛酸亚锡-乙二醇共引发体系的存在下,通过熔融开环聚合制备出了端羟基聚(丙交酯-co-对二氧环己酮)(HO-P(LA-co-PDO)-OH).这种同时具有PLA、GA和EG结构单元的大分子二醇可望成为一种降解速率可控、在循环系统中停留时间可调的新型药物载体材料.采用DSC、~1H NMR、~(13)C NMR和GPC-MALLs等对其结构和热学性能进行了表征.分子量检测结果表明,HO-P(LA-co-PDO)-OH的分子量随原料中PDO/LA摩尔比的减小而增大.     

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.     

Synthesis of uniform TiO2 nanoparticles with egg albumen proteins as novel biotemplate

A novel bio-templated route was reported for the fabrication of uniform and well dispersed TiO, nanoparticles using denatured egg albumen (EA) proteins network as template. Anatase TiO2 nanoparticles of ca. 9 nm with narrow size distribution were obtained under employed reaction conditions, as proved by the XRD and TEM results. The as-prepared TiO2 nanoparticles were further characterized by means of XPS, FTIR, TG-DTA and UV-Vis. Based on the characterization results, a possible process of heat-induced denatured protein network as template matrix to fabricate TiO2 nanoparticles was carefully proposed. The method with egg albumen as bio-template provides us a cheap, green and repeatable route for the fabrication of nanoparticles under mild conditions.     

Synthesis and characterization of solar photoactive TiO2 nanoparticles with enhanced structural and optical properties

The structural, morphological, and optical properties of the sol–gel derived TiO₂ nanoparticles at different pH and calcination temperature were investigated in the present study. X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), UV–Visible(Vis) spectroscopy, energy dispersive studies (EDS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoluminescence (PL) spectroscopy, BET surface area analysis, and Barrett-Joyner-Halenda (BJH) pore size distribution and pore volume analysis were used to characterize the prepared TiO₂ photocatalyst. The range of crystallite size and band gap of the synthesized TiO₂ samples were in the range of 20–80?nm and 2.5–3.2?eV respectively. The photocatalytic performance of prepared TiO₂ photocatalysts was evaluated by photodegradation of Methylene Blue (MB) solution under simulated solar irradiation. Results illustrate that the synthesized TiO₂ exhibits visible light activity at higher calcination temperature. Crystallinity and surface area plays a vital role in the overall performance of the prepared TiO₂ photocatalyst.     

Anatase TiO2 nanoparticles/carbon nanotubes nanofibers: preparation, characterization and photocatalytic properties

In the present work, we report the preparation and photocatalytic properties of hybrid nanofibers/mats of anatase TiO₂ nanoparticles and multi-walled carbon nanotubes (MWNTs) using combined sol–gel and electrospinning techniques. Poly(vinyl pyrrolidone) is used as a base polymer in the electrospinning suspension to assist the formation of nanofibers and subsequently removed by calcination. The hybrid nanofibers are characterized using XRD, Raman spectra, FT-IR, XPS, SEM, TEM and N₂ adsorption measurements. The results show that MWNTs are encapsulated by in-situ formed anatase TiO₂ nanoparticles, with chemical bonding C–O–Ti between anatase TiO₂ nanoparticles and MWNTs. Hybrid nanofibrous mats with moderate content of MWNTs (mass ratio TiO₂:MWNTs = 100:20) exhibit enhanced adsorption ability and excellent photocatalytic activity. The composition, diameter and morphology of hybrid nanofibers can be tuned by varying sol–gel formulation, electrospinning parameter and post-treatment condition. TiO₂/MWNTs hybrid nanofiber and mats have promising applications in water purification and solar cell areas.     

Synthesis and characterization of N-doped TiO2/ZrO2 visible light photocatalysts

Zirconia and nitrogen-doped TiO₂ powder was synthesized using a polymer complex solution method for the preparation of an enhanced visible light photocatalyst. The produced catalysts were characterized via the Brunauer, Emmett, and Teller method (BET), X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, and UV–Vis spectrophotometry analyses. The N-doped TiO₂/ZrO₂ photocatalyst showed a high specific surface area and small crystal sizes. The XPS spectra of the N-doped TiO₂/ZrO₂ sample indicated that nitrogen was doped into the TiO₂ lattice and enhanced the photocatalytic activity. The UV–Vis absorption spectra of the N-doped TiO₂/ZrO₂ sample noticeably shifted to the visible light region compared to that of the TiO₂. The photocatalytic activities of the prepared catalysts were evaluated for the decomposition of gaseous NO_x under UV and visible light irradiations. The photocatalytic activities of N-doped TiO₂/ZrO₂ were much greater than those of commercial Degussa P25 in both the UV and visible light regions. The high photocatalytic activity can be attributed to stronger absorption in the visible light region, a greater specific surface area, smaller crystal sizes, more surface OH groups, and to the effect of N-doping, which resulted in a lower band gap energy.     

纳米TiO2粉体的低温制备

采用液相沉积法制备锐钛矿型TiO2纳米光催化粉体,研究了沉积温度、反应物的摩尔比、沉积时间、[TiF6]^2-水溶液的浓度等对TiO2粉体性能的影响。用甲基橙的光催化降解表征了所制备的TiO2粉体的光催化活性。结果表明光催化活性最佳的实验参数为：温度为90℃,(NH4)2TiF6与H3BO3的摩尔比为1：2。5,沉积时间为1h,加水量为320ml。     

Synthesis and dye-sensitized solar cell performance of nanorods/nanoparticles TiO2 from high surface area nanosheet TiO2

High surface area nanosheet TiO2 with mesoporous structure were synthesized by hydrothermal method at 130 degrees C for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The as-synthesized nanosheet TiO2 had average pore diameter about 3-4 nm. The BET surface area and pore volume of the sample were about 642 m(2)/g and 0.774 cm(3)/g, respectively. The nanosheet structure after calcinations were changed into nanorods/nanoparticles composite with anatase TiO2 structure at 300-500 degrees C (10-15 nm in rods diameter and about 5-10 nm in particles diameter). The solar energy conversion efficiency (eta) of the cell using nanorods/nanoparticles TiO2 (from the nanosheet calcined at 450 degrees C for 2 h) with mesoporous structure was about 7.08% with Jsc of 16.35 mA/cm(2), Voc of 0.703 V and ff of 0.627; while eta of the cell using P-25 reached 5.82% with Jsc of 12.74 mA/cm(2), Voc of 0.704 V, and ff of 0.649.     

单分散纳米TiO2的合成及表征

以钛酸四丁酯为原料和三乙醇胺为形态控制剂,采用溶胶-凝胶-水热法可以简单快速地合成单分散的TiO2纳米粒子.研究了反应物料配比、凝胶形成温度、水热处理温度等反应条件对粒子粒径及分散性的影响.采用XRD和TEM等手段对粒子的结构与形貌进行了表征.结果表明,三乙醇胺与钛酸四丁酯物质的量配比为2:1,凝胶形成温度为100℃,水热处理温度为140℃时,所合成的TiO2粒子分散性最好.     

Sol-gel synthesis, characterization and bioactivity of polycaprolactone/SiO2 hybrid material

A novel organic/inorganic hybrid material was synthesized by sol-gel method from a multicomponent solution containing tetramethylorthosilicate (TMOS), polycaprolactone (PCL), water, and methilethylketone (MEK). The interpenetrating network structure is realized by hydrogen bonds between Si—OH group (H donator) in the sol-gel intermediate species and carboxylic group (H-acceptor) in the repeating units of the polymer.The presence of hydrogen bonds between organic/inorganic components of the hybrid material was proved by FTIR analysis. The morphology of the hybrid material was studied by scanning electron microscope (SEM). The structure of a molecular level dispersion has been disclosed by atomic force microscope (AFM), pore size distribution and surface measurements. The bioactivity of the synthesized hybrid material has been showed by the formation of a layer of hydroxyapatite on the surface of PCL/SiO₂ samples soaked in a fluid simulating the composition of the human blood plasma.     

Synthesis of TiO2 nanoparticles through the Gel Combustion process

Nanosized titania particles have been synthesized through the Gel Combustion process. The synthesis was carried out by starting from a common and low-cost titanium precursor and hydrogen peroxide as combustible substance. The process led to a significant gas development and the as-synthesized nanoparticles showed a low degree of crystallinity and mean dimension of 20 nm. Different thermal treatments were performed so as to investigate their effect on the structural properties and on the particle size of the synthesized products. The optimal temperature was set at 300 °C, giving pure anatase TiO₂ nanopowders with a good level of crystallinity, an average particle size of 50 nm and a high value of specific surface area.