纳米TiO2改性沥青的制备及其流变性能研究

选定一种纳米TiO₂粉体作为改性剂,制备不同掺量的纳米改性沥青,并对改性后的沥青进行流变指标试验,分析纳米粉体对不同基质沥青的改性效果。研究认为,纳米粉体在改善沥青稠度方面有着明显的效果,远大于普通填料带来的增稠效果。纳米TiO₂的加入对高温性能的改善有限,且对延展性能有消极影响,但可以提高改性沥青耐疲劳性能。以70号、90号沥青为基础的改性沥青中,两种改性沥青均在3.5%TiO₂掺量时体现出最大的疲劳次数。     

纳米TiO2的性能及其研究进展

纳米二氧化钛是一种新型无机材料,它具有光催化活性,能利用太阳光催化降解很多有毒、有害的物质,具有广阔的应用前景,近年来已成为材料研究领域的热点.本文介绍了纳米TiO2膜的光催化机理、电荷传输特性及其制备方法、现阶段国内外研究的热点以及研究进展.     

电化学法制备纳米TiO2/聚邻甲苯胺复合膜

用3mol     

正交设计法制备纳米TiO2改性涂料

针对纳米TiO2在涂料中不易分散且分散稳定性差,易发生二次团聚的问题,根据纳米粒子的团聚及分散原理,利用正交设计方法,研究了纳米TiO2含量、乳液配比、分散剂用量及超声分散时间对涂料性能的影响,确定了最佳配方。     

微乳液法制备纳米SiO2/TiO2及其光催化性能

以无机物聚合硅酸为硅源、硫酸钛为钛源,采用微乳液法制备了SiO2/TiO2复合光催化剂,考察了制备条件对SiO2/TiO2光催化活性的影响,并利用SEM、FTIR、XRD和BET等技术手段对光催化剂进行了表征。结果证明,SiO2和TiO2颗粒之间存在着强的相互作用,形成了Ti-O-Si键,从而抑制了TiO2粒径的增大,延缓了TiO2由锐钛矿相向金红石相的转变。对甲基橙等染料的光催化降解实验结果表明,SiO2/TiO2的光催化活性并非随着TiO2的含量增加而提高,当硅与钛物质的量比为1∶1并在160℃的温度下水热合成2.5 h时,SiO2/TiO2光催化剂在紫外光照15 min后对甲基橙的脱色率为85.5%,与同等条件下制备的TiO2相比具有更好的光催化活性和更大的比表面积。     

纳米TiO2粉体的制备及其光催化性能研究

以四氯化钛为原料,采用水解法制备了纳米TiO2粉体。用X射线衍射仪(XRD)、扫描电镜(SEM)对制备的粉体进行了表征,并研究了其对甲基橙的光催化降解性能。结果表明:产物为纯锐钛矿相纳米TiO2,一次粒度在100 nm以内;对甲基橙具有一定的催化降解作用,热处理温度为500℃时,产物的光催化活性较高。     

纳米SiO2/TiO2复合粉体的制备及表征

以Na2SiO3为原料,采用非均匀成核法在纳米TiO2基体上制备了SiO2表面保护膜层,通过红外光谱、X射线光电子能谱、扫描电镜、粒径测量、BET比表面积测量分析,证实纳米TiO2颗粒表面包覆了一层均匀致密的SiO2纳米膜,而且两者是以化学键合方式结合在一起。分散性能测试表明:纳米SiO2/TiO2复合粉体的分散性能明显提高。     

纳米TiO2对环氧树脂力学性能的影响

研究了纳米TiO2含量对纳米TiO2/环氧复合材料弯曲性能和拉伸性能的影响.结果表明,超声作用可以使纳米TiO2均匀分散于树脂体系中;环氧树脂中添加纳米TiO2可以同时增强增韧环氧树脂,当纳米TiO2含量为3%时,纳米TiO2/环氧的弯曲强度和拉伸强度比未添加纳米TiO2时分别提高了72%和65%.     

纳米TiO2抗菌剂的改性及在抗菌塑料中的应用研究

纳米TiO2具有强氧化性和亲水性,在抗菌剂方面有广泛的应用前景。由于TiO2的带隙能较高,需在紫外光照射下有较好的抗菌效果,目前国内外学者采用金属及非金属离子掺杂的方法改进TiO2在可见光下的光催化活性,增强纳米TiO2抗菌剂在可见光下的抗菌能力,本文对纳米TiO2抗菌剂改性研究情况及其在抗菌塑料中的应用情况进行了综述。     

TiO2纳米带的制备及应用研究进展

对TiO2纳米带的主要制备方法以及应用前景等方面进行了综述。并展望了TiO2纳米带今后的研究方向。     

水热法制备BaF2粉体材料

以销酸钡和氟化铵为原料,以柠檬酸为络合剂,采用水热法合成了BaF2粉体。用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对产物的形貌和结构进行了表征,结果表明反应温度及pH值对产物的形状和尺寸有很大影响,可以通过改变温度和pH值调控产物的形貌。     

正交设计在电刷研制中的应用

介绍了正交设计在电刷研制中的应用。通过对试验数据的分析,找出了最佳配方方案。实验证明,按该方案研制的电刷,符合电机对电刷的使用要求,达到了预定目标。     

正交实验法在超级活性炭研制中的应用

首次将正交实验法运用于超级活性炭的研制,并对各活化因素进行了直观和方差分析及效应考察,得出高硫焦制备超级活性炭的最佳工艺条件和各活化因素对活性炭性能影响程度大小。制备出BET比表面积高达3886m^2/g的超高比表面积活性炭。将原料的结构与活性炭超高比表面积的相关性给予一定程度的解释。     

DBS包覆钛盐水解制备纳米TiO2的研究

以Ti(SO4)2水溶液为前驱体,NH3@H2O为沉淀剂,以十二烷基苯磺酸钠(dodecyl benzene sulfonate,DBS)为表面活性剂,采用常温水解沉淀法制备出了纳米TiO2粉体.用XRD测试粉体的晶相组成;用TEM分析粉末的晶体形貌.研究了溶液的pH、表面活性剂、煅烧温度等对纳米TiO2颗粒尺寸的影响.结果表明当溶液pH为2.0～4.0,分散剂质量分数为1.5%时,水解沉淀得到的TiO2晶粒尺寸在10～20 nm之间.研究烧结过程中晶粒的变化时发现由于DBS的包覆,有效地抑制了煅烧过程中晶粒的长大.     

Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions

Cu₂O/TiO₂, Bi₂O₃/TiO₂ and ZnMn₂O₄/TiO₂ heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu₂O, Bi₂O₃ and ZnMn₂O₄ are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu₂O/TiO₂ and Bi₂O₃/TiO₂ by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.     

TiO2, TiO2/Ag and TiO2/Au photocatalysts prepared by spray pyrolysis

TiO₂, TiO₂/Ag and TiO₂/Au photocatalysts exhibiting a hollow spherical morphology were prepared by spray pyrolysis of aqueous solutions of titanium citrate complex and titanium oxalate precursors in one-step. Effects of precursor concentration and spray pyrolysis temperature were investigated. By subsequent heat treatment, photocatalysts with phase compositions from 10 to 100% rutile and crystallite sizes from 12 to 120 nm were obtained. A correlation between precursor concentration and size of the hollow spherical agglomerates obtained during spray pyrolysis was established. The anatase to rutile transformation was enhanced with metal incorporations and increased precursor concentration. The photocatalytic activity was evaluated by oxidation of methylene blue under UV-irradiation. As-prepared TiO₂ particles with large amounts of amorphous phase and organic residuals showed similar photocatalytic activity as the commercial Degussa P25. The metal incorporated samples showed comparable photocatalytic activity to the pure TiO₂ photocatalysts.     

正交实验法在高硫容成型活性焦制备中的应用

用正交实验法制备了成型活性焦 ,并对各种因素进行了方差分析和效应考察 ,得到了用高挥发分彬县煤制备高硫容成型活性焦的工艺条件 :炭化温度 40 0℃ ,炭化时间 2 0 min,活化温度 95 0℃ ,活化时间 60 min,影响程度为 :活化时间 >活化温度 >炭化温度 >炭化时间 ,并从机理上给以一定的解释     

Dy2Ce2O7和Y2Ce2O7稀土铈酸盐的制备及热导率

采用固相反应法在1600℃下保温10小时制备了Dy2Ce2O7和Y2Ce2O7陶瓷材料。分析了其相组成、微观组织和热导率。XRD结果表明,成功合成了具有萤石晶体结构的单一相Dy2Ce2O7和Y2Ce2O7。其组织结构致密,晶界清晰,无未反应物或杂质相存在。由于氧空位以及取代原子与基质原子之间的质量差异所导致的声子散射,使得Dy2Ce2O7和Y2Ce2O7具有比YSZ更低的热导率,这些结果表明,Dy2Ce2O7和Y2Ce2O7均可用作将来热障涂层用候选材料。     

Spontaneously ordered TiO2 nanostructures

Titanium dioxide thin films were deposited on quartz substrates kept at different O₂ pressures using pulsed laser deposition technique. The effects of reactive atmosphere and annealing temperature on the structural, morphological, electrical and optical properties of the films are discussed. Growth of films with morphology consisting of spontaneously ordered nanostructures is reported. The films growth under an oxygen partial pressure of 3 × 10⁻⁴ Pa consist in nanoislands with voids in between them whereas the film growth under an oxygen partial pressure of 1 × 10⁻⁴ Pa, after having being subjected to annealing at 500 °C, consists in nanosized elongated grains uniformly distributed all over the surface. The growth of nanocrystallites with the increase in annealing temperature is explained on the basis of the critical nuclei-size model.     

Combined TiO2/SiO2 mesoporous photocatalysts with location and phase controllable TiO2 nanoparticles

Combined TiO₂/SiO₂ mesoporous materials were prepared by deposition of TiO₂ nanoparticles synthesised via the acid-catalysed sol–gel method. In the first synthesis step a titania solution is prepared, by dissolving titaniumtetraisopropoxide in nitric acid. The influences of the initial titaniumtetraisopropoxide concentration and the temperature of dissolving on the final structural properties were investigated. In the second step of the synthesis, the titania nanoparticles were deposited on a silica support. Here, the influence of the temperature during deposition was studied. The depositions were carried out on two different mesoporous silica supports, SBA-15 and MCF, leading to substantial differences in the catalytic and structural properties. The samples were analysed with N₂-sorption, X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) to obtain structural information, determining the amount of titania, the crystal phase and the location of the titania particles on the mesoporous material (inside or outside the mesoporous channels). The structural differences of the support strongly determine the location of the nanoparticles and the subsequent photocatalytic activity towards the degradation of rhodamine 6G in aqueous solution under UV irradiation.