利用偏钛酸浆料制备大比表面纳米管钛酸工艺的研究

以偏钛酸浆料为原料通过水热法合成了纳米管钛酸,并采用TEM,比表面积测定仪等分析手段观察其形貌和管径大小,测定了其比表面积和孔体积.同时运用正交实验法考察了反应温度、反应时间对纳米管钛酸比表面积和孔体积的影响.实验结果表明,所制备的纳米管钛酸平均比表面积高达 340m2 /g,最佳的制备工艺是:工业碱NaOH的质量分数为 25. 7 %、偏钛酸浆料的质量分数为 17. 1 %、后处理酸度为pH=1、反应温度为 120℃、反应时间为 20h.     

过渡金属离子置换钛酸纳米管的制备和光催化活性

TiO2纳米粉体和纳米膜材料在光催化降解大气和水中的污染物等方面具有广泛的应用[1]。近年来,以TiO2为原料与浓N aO H反应合成的钛酸纳米管具有比其原料TiO2更大的表面积和孔体积,且对丙烯有光催化氧化降解活性而备受关注[2]。以往在对TiO2纳米粉体和纳米膜材料在光催化研究中,人们发现由于光激发产生的电子与空穴的复合,导致光量子效率很低。为克服这个缺点,人们使用过渡金属离子掺杂等多种手段对TiO2进行改性[3]。但钛酸纳米管相类似的研究还未见报道。对钛酸纳米管的结构和组成的研究表明[4],此纳米管状物的组成是N axH2-xTi3O7,…     

钛酸纳米管的化学修饰及发光性能的稳定化

钛酸纳米管表面富有羟基, 利用十六醇与Ti-OH发生脱水反应对钛酸纳米管进行化学修饰. 通过透射电子显微镜、红外光谱和荧光光谱等方法研究了表面修饰对钛酸纳米管的结构及光学性质的影响. 与未修饰的钛酸纳米管相比, 不溶于有机溶剂的钛酸纳米管修饰后溶于氯仿、甲苯中, 为进一步用LB膜技术组装钛酸纳米管提供了条件, 并且钛酸纳米管表面修饰的有机层有效抑制了纳米管表面对水的吸附, 解决了钛酸纳米管在空气中久置或有水气氛下特殊的可见区吸收和荧光发光现象受到影响的问题, 使钛酸纳米管的发光性质稳定, 为钛酸纳米管的广泛应用奠定了基础.     

纳米金-钛酸纳米管复合材料的合成与表征

以氯金酸和钛酸钠米管(NTA)为原料,柠檬酸三钠为稳定剂,硼氢化钠为还原剂,于室温条件下合成了一种金纳米颗粒-钛酸纳米管(GNPs-NTA)复合纳米材料;利用红外光谱仪、透射电镜、X射线粉末衍射仪等分析了产物的化学键合特征、微结构及相组成,并考察了产物对辣根过氧化酶(HRP)结构和生理活性的影响.结果表明,合成的纳米金颗粒粒径(平均5.3nm)分布窄,且均匀分布于钛酸纳米管表面.此外,HRP与GNPs-NTA复合纳米材料充分振荡混合后仍能保持其二级结构不变,有利于保持其生理活性.     

硫辛酸修饰钛酸纳米管吸附亚甲基蓝的性能

在水热法制备钛酸纳米管（Titanate nanotubes,TNTs）的基础上,再通过浸渍法将硫辛酸（Lipoic acid,LA）修饰到钛酸纳米管上,得到硫辛酸修饰的钛酸纳米管（TNTs-LA）。通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线衍射（XRD）、X光电子能谱仪（XPS）和傅里叶变换红外光谱（FT-IR）等仪器对材料进行表征,并以亚甲基蓝（MB）的吸附实验评价其吸附性能。结果表明,TNTs-LA对MB的吸附主要集中于前30 min,60 min可达吸附平衡。MB的去除与溶液p H值有关,且符合二级反应动力学方程,吸附过程是一个多种机制共同作用的结果。Langmuir等温模型拟合得出TNTs-LA对MB的最大吸附量为216.98 mg/g,有较高的吸附能力。     

负载金的纳米管钛酸光催化氧化一氧化碳

 用化学方法制备了负载金的纳米管钛酸(Au/H2Ti2O4(OH)2)光催化剂,并用TEM,XPS,XRD和DRS等技术对催化剂进行了表征. 结果表明,经573 K处理后,纳米管钛酸表面及管内均有零价的金颗粒存在. 与纳米管钛酸(H2Ti2O4(OH)2)相比,Au/H2Ti2O4(OH)2具有明显的CO光催化氧化活性,但在暗态时无活性. 经分析认为,暗态时Au与纳米管相互接触的周界处不活泼,故催化剂无CO催化氧化活性; 紫外光照射下,纳米管激发产生e--h+对,e-从纳米管转移到Au0上, 使纳米管和Au-在接触周界处产生相互作用,形成活性位,导致CO催化氧化反应发生.     

镶嵌CdS的纳米管钛酸制备及其光催化性能研究

制备了镶嵌硫化镉的纳米管钛酸,并用透射电镜(TEM)、X射线衍射(XRD)、扩散反射(DRS)等工具进行了表征.丙烯的光催化氧化研究结果表明,镶有CdS与未镶CdS的纳米管钛酸作为光催化剂,对丙烯的光催化去除活性相近.     

纳米管钛酸和二氧化钛的暗态吸附性能

研究了在暗态下纳米管钛酸,TiO2(A),P25TiO2对水溶液中活性艳红X 3B的吸附性能.结果表明,pH值不同时,三者对活性艳红X-3B的吸附量不同,分析了它们吸附性能不同的原因.     

负载银纳米管钛酸催化剂的制备

采用光催化还原法制备了载银纳米管钛酸,通过TEM可以看到纳米管钛酸表面附着有银颗粒,XPS和XRD等结果显示银颗粒是以单质银的形式存在.对亚甲基蓝光催化降解实验结果表明:载银纳米管钛酸催化剂的催化活性比未载银纳米管钛酸催化剂的活性高.     

过渡金属离子置换钛酸(盐)纳米管的合成和表征

以掺杂(Mn、Cr、Cu)的锐钛矿相二氧化钛纳米粉体为前驱体, 采用水热法合成了过渡金属离子置换的钛酸(盐)纳米管, 并用扫描电镜(SEM)、透射电镜(TEM)、能谱元素分析(EDX)、粉末X射线衍射(XRD)、 荧光发射光谱(PL)和拉曼光谱(Raman)对产物进行了表征. 结果表明, 过渡金属离子置换的钛酸(盐)纳米管荧光发射强度随金属离子的置换都有不同程度的降低, 一般认为低电子空穴对复合率意味着高光量子效率. 期望置换后的钛酸(盐)纳米管有可能在催化领域得到应用.     

Sol-Gel Processing of Some Electroceramic Powders

This review deals with the solution-sol-gel processing (SSG) of powders such as BaTiO₃, MgTiO₃, PbTiO₃, Bi₄Ti₃O₁₂, La₂Ti₂O₇, Pb(Zr_0.52Ti_0.48)O₃, Pb(Mg_1/3Nb_2/3)O₃ and Ba(Mg_1/3Ta_2/3)O₃. Fine powders of good sinterability can be easily obtained at low temperatures although the process can be expensive and time consuming. We propose a nanocomposite route which utilizes nanophases of different components as a cost-effective alternative to sol-gel process for powder preparation.     

钛酸盐(钴、镓)沸石分子筛的合成与表征

钛酸钴;钛酸镓;水热合成;钛酸盐(钴、镓)沸石分子筛的合成与表征     

Synergistic effects of CdS in sodium titanate based nanostructures for hydrogen evolution

Synergistic effect of CdS decorated sodium titanate nanostructures showed enhanced H₂ production abilities. The confinement effect and synergistic effect of decorated CdS inside the sodium titanate nanotubes are investigated.     

Thermoanalytical study of the synthesis of Na<Subscript>0.5</Subscript>Bi<Subscript>0.5</Subscript>TiO<Subscript>3</Subscript> ferroelectric

The study presents results of examination on Na_0.5Bi_0.5TiO₃ (NBT) ferroelectric synthesis through intermediate binary compound Bi₄Ti₃O₁₂ (BIT). The first stage of the study related to obtaining BIT from oxide precursors, i.e. Bi₂O₃ and TiO₂. The second stage included obtaining NBT from Bi₄Ti₃O₁₂, Na₂CO₃ and TiO₂. Two polymorphic modifications of TiO₂ (anatase, rutile) and diversified initial homogenization of raw material batches were applied during examination.     

Effect of ZnO on sintering and microwave dielectric properties of 0.5CaTiO3-0.5 (Li0.5La0.5) TiO3 ceramics

The novel calcium titanate-lithium lanthanum titanate doped with zinc oxide (0.10, 0.30, and 0.50 mol. %) ceramic samples were prepared by solid-state reaction route. The phase formation, microstructure, densification, and microwave dielectric properties were investigated. It was found that the doping with zinc oxide led to a decrease in sintering temperature by 25 ^oC as compared with pure calcium titanate lithium lanthanum titanate due to the liquid phase effect. Also, the calcium titanate lithium lanthanum titanate (10ZCTLLT&30ZCTLLT)) doped with lower zinc oxide (0.10 and 0.30 mol. %) led to higher densification parameter. This was followed by increasing the zinc oxide doping up to (0.50 mol. %) which resulted in a decrease in densification and microwave dielectric properties which may be attributed to increase in porosity and grain growth upon the evaporation of zinc and oxygen vacancy. This led to the increase in dielectric loss (≈10 × 10^?4) value with 50ZCTLLT. Hence, the best result of microwave dielectric characteristics was obtained for 0.5CaTiO₃–0.5(Li_0.5La_0.5)TiO₃ with (0.10 and 0.30 mol. % ZnO) 10ZCTLLT and 30ZCTLLT ceramic samples sintered at 1175 ^oC/2h, with low dielectric constant (ε_r) = 4.4–10.5, very low dielectric loss = 1.07-2.23 × 10^?4 and high quality factor (Q x ?) ≈59-55 × 10⁴ at 8 GHz. Consequently, they can be used not only in wireless satellite communications technology but also can be used in the fifth-generation telecommunication 5G technology construction.     

几种钛酸钾纤维的合成及其相关性研究

本文以Ｋ＿２ＣＯ＿３和ＴｉＯ＿２为主要原料，采用混练－干燥－煅烧三步法合成出了Ｋ＿２Ｔｉ＿２Ｏ＿５、Ｋ＿２Ｔｉ＿４Ｏ＿９、Ｋ＿２Ｔｉ＿６Ｏ＿１３三种形式的钛酸钾纤维物质。测定了它们的ＸＲＤ、ＤＴＡ－ＴＧ、ＳＥＭ、ＩＣＰ、激光拉曼等有关特征数据和谱图，并对它们之间的相互关系进行了研究。     

钛酸酯催化碳酸二甲酯与苯酚酯交换反应

The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 25 h and DMC∶phenol∶ Ti(OBu) 4 molar ratio of 1 5∶1∶0 05. The selectivity for DPC could reach 12.2% when the reaction time was 30 h. The tetrabutyl titanate catalyst showed a higher catalytic activity than tetraphenyl titanate.     

Co-SrTiO3上光催化分解水制氢的性能研究

氢能在使用过程中不会给环境带来任何污染,是未来最理想的能源。但目前的氢气生产方法能耗较高,同时伴随着严重的环境污染,显然不适合大规模生产能源用氢气。洁净化生产氢气方法的开发备受世人的关注,吸引了大量的科研人员从事这方面的研究。其中以半导体氧化物为催化剂,光催化分解水制氢被认为是最有前途的方法。经过几十年的努力,取得了很大的进步,先后开发出在紫外光照射下可以将蒸馏水分解为氢气和氧气的光催化剂,如TiO2犤1犦、SrTiO3犤2犦、Na2Ti6O13犤3犦、BaTi4O9犤4犦、K2La2Ti3O10犤5犦、K4Nb6O17犤6犦、ZrO2犤7犦等;可见…     

Rheological Characterization of BaTiO3 Sol-Gel Transition

BaTiO₃ gels were prepared by hydrolysis and polycondensation reactions between titanium isopropoxide and barium hydroxide in presence of methoxyethanol, methanol and water. The rheology of the sol-gel transition was studied with a rheometer allowing low amplitude sinusoidal oscillations. Experimental data show a continuous increase in the complex viscosity along with time, showing the progressive character of the transition. The influence of synthesis operating variables was studied. The gelation time, which definition is based on viscoelastic measurements, increases exponentially when the water content is increased, when the dilution due to the methoxyethanol is reduced or when the temperature is lowered. Different growth models were used for the characterization of the particles in the solution. These models suggest that the polymerisation first produces spherical particles (mass fractals) and that these spherical particles then agglomerate to form a linear network.     

Elaboration of nano titania-magnetic reduced graphene oxide for degradation of tartrazine dye in aqueous solution

In this paper, magnetic nanocomposites are synthesized by loading reduced graphene oxide (RG) with two components of nanoparticles consisting of titanium dioxide (TiO₂) and magnetite (Fe₃O₄) with varying amounts. The structural and magnetic features of the prepared composite photocatalysts were investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis/DRS), Raman and vibrating sample magnetometer (VSM). The resulting TiO₂/magnetite reduced graphene oxide (MRGT) composite demonstrated intrinsic visible light photocatalytic activity, on degradation of tartrazine (TZ) dye from a synthetic aqueous solution. Specifically, it exhibits higher photocatalytic activity than magnetite reduced graphene oxide (MRG) and TiO₂ nanoparticles. The photocatalytic degradation of TZ dye when using MRG and TiO₂ for 3 h under visible light was 35% and 10% respectively, whereas for MRGT it was more than 95%. The higher photocatalytic efficiency of MRGT is due to the existence of reduced graphene oxide and magnetite which enhances the photocatalytic efficiency of the composite in visible light towards the degradation of harmful soluble azo dye (tartrazine).