Al2O3孔径调制及助剂对Pd/Al2O3催化性能的影响

研究了纳米载体Al2O3的合成条件对孔径分布的影响，并测定了载体孔径．结果表明，纳米载体Al2O3的合成条件对其孔径分布的影响顺序依次为陈化时间、NH4HCO3的过量系数、反应温度、加料方式及Al^3 浓度．在此基础上，又研究了催化剂活化预处理条件、助剂掺杂与修饰及催化反应条件对催化反应性能的影响，评价了催化剂活性．结果表明，以共沉淀法掺杂助剂所得催化剂较浸渍法助剂修饰所得催化剂活性更高，以快速氧化活化所得催化剂活性较高，而助剂Ce掺杂的催化剂比助剂K，Mg，ZrO2掺杂的催化剂具有较高的催化活性。     

Preparation of ZAO film by low-temperature hydrothermal approach and its electrical property

Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.     

Preparation,Structures,Thermal Properties and Sintering Behaviors of B_2O_3-SiO_2-ZnO-BaO-Al_2O_3 Glass

B_2O_3-SiO_2-ZnO-BaO-Al_2O_3 glass with different Al_2O_3 contents(1mol%, 3mol%, 5mol%, and 7mol%) was prepared, and it was intended to be used as lead-free and low-melting glass sealants for solid oxide fuel cells. The effects of Al_2O_3 content on the structures, thermal properties, and sintering behaviors of the B_2O_3-SiO_2-ZnO-BaO-Al_2O_3 glass were investigated in detail. The Al_2O_3 content largely influenced the structures and thermal properties of the glass. When the Al_2O_3 content 5mol%, the transition temperature of the glass decreased with the Al_2O_3 content, while the crystallization temperature increased with the Al_2O_3 content. However, higher Al_2O_3 content degraded the stability of the glass. The B_2O_3-SiO_2-ZnO-BaO-Al_2O_3 glass with 5 mol% Al_2O_3 content exhibits the optimal sintering densification characteristics and can be used as glass sealants for solid oxide fuel cells.     

Al2O3含量对Cu-ZnO-Al2O3-SiO2催化剂性能的影响

研究了Al2O3含量对Cu-ZnO-Al2O3-SiO2催化剂在CO2加氢合成二甲醚中催化性能的影响,并用XRD,H2-TPR,XPS,NH3-TPD和CO2-TPD等手段进行了表征.研究结果表明,Al2O3延缓了CuO和ZnO晶粒的长大,同时使催化剂变得难以还原.加入的Al2O3富集于催化剂表面,改变了催化剂表面Cu2+和Zn2+的摩尔分数.Al2O3还与SiO2产生无定形SiO2-Al2O3混合相,提供二甲醚合成所必需的酸碱中心.反应结果表明,Al2O3在催化剂中的质量分数低于1.4%时,对转化率的提高有促进作用;当Al2O3在催化剂中的质量分数为4.0%时,甲醇合成以及甲醇脱水的活性中心呈现出较好的"协同催化效应",目标产物二甲醚的收率最高.研究认为,Al2O3通过影响CuO与Al2O3之间的相互作用以及催化剂的表面酸性,从而使催化剂对CO2加氢合成二甲醚表现出不同的催化性能.     

STUDY OF SURFACE RESISTIVITY MODIFICATION IN Al_2O_3 CERAMIC IMPLANTED BY Fe~(2 )

The implanted ion range, the depth profileand the film sttucture of the implanted layer werestudied; the carrier concentration and the mobilitywere measured; the conductivity mechanism of thefilm implanted Fe into Al_2O_3 ceramic was discussed.The conclusion is that the implanted Fe~(2 ) ions moveinto Al_2O_3 lattice and replace Al~(3 ) to form subs-titution impurities so that the ion implanted lat-tice, as compared with the original one, presentsan effective negative charge which forms a negativecharge center. A vacancy is bound arround it, andan acceptor is introduced in the forbidden band.     

在Ni-Mo/Al_2O_3上催化裂化轻汽油的选择性加氢

制备了以Al2O3为载体的镍基双金属选择性加氢催化剂,并用于催化裂化轻汽油的选择性加氢反应。考察了载体焙烧温度、金属镍与钼的负载量对催化剂选择性加氢性能的影响。结果表明,适当的焙烧温度降低了催化剂的比表面积和表面酸性,提高了催化剂的稳定性。助剂钼的加入有利于活性组分镍的均匀分散。在反应温度为80℃、空速为10h-1、氢油体积比为10、压力为1.5MPa的工艺条件下,采用Ni-Mo/Al2O3催化剂,催化裂化轻汽油中二烯烃转化率达到98%以上。制备的选择性加氢催化剂具有良好的活性和选择性,可以在选择性加氢领域获得应用。     

铝对草酸法生产混合稀土氧化物的影响

本文研究了用草酸法从离子型稀土矿的浸出液中得到混合稀土氧化物时,杂质铝的影响。找到稀土、铝、草酸根等离子间的定量关系。得到随着铝含量的增加,要使稀土定量沉淀,必须加入过量草酸的规律。这是由于草酸沉淀稀土过程中 Al~(3+)·Re~(3+)和 C_2O_4~(2-)离子间形成了复杂的溶解性较大的配合物所致。     

EVA/Al_2O_3纳米复合材料的结构与性能

以纳米A l2O3为增强材料,制备了EVA/A l2O3纳米复合材料,并采用FESEM、FT-NIR、SEM等测试手段表征纳米A l2O3微粒在EVA基体中的分散性与结构,研究了纳米A l2O3的质量分数对纳米复合材料力学性能的影响。结果表明:A l2O3微粒以20 nm左右的粒径分散于EVA基体中,并与EVA形成化学键合结构,复合材料的断裂机理发生变化。填充质量分数为0.5%的纳米A l2O3微粒时,拉伸强度提高13.0%;当加入的纳米A l2O3的质量分数为1%时,断裂伸长率可提高13.3%。     

La-Sr掺杂和助成胶剂对氧化铝热稳定性的影响

通过水溶液成胶和聚乙二醇络合助成胶制备了不同结构的氧化铝,利用XRD、BET及SEM等表征测试手段研究了镧、锶物种双组分改性对氧化铝热稳定性的影响.结果表明,不同温度焙烧时,双组分掺杂改性能提高纯氧化铝的比表面积,改善其热稳定性,共同掺杂改性时,可与氧化铝作用形成复合氧化物占据其间隙,防止铝离子的迁移,从而提高氧化铝的热稳定性和比表面积;添加聚乙二醇助成胶时,低温提高氧化铝比表面积的机理是在氧化铝粒子中间形成许多孔道,高温时,则通过La、Sr物种补充到氧化铝表面的空位中阻止铝离子的迁移来提高氧化铝的热稳定性和比表面积.     

Al2O3/Ti-Al复合材料的抗高温氧化性研究

利用氧对金属Ti、Al粉的部分氧化，原位合成了Ti—Al金属间化合物和氧化铝，从而制备出了Al2O3／Ti—Al复合材料，通过氧化增重实验研究了材料的抗高温氧化性能，发现随着原始配比中Al含量和烧成温度的增加，复合材料的抗高温氧化性能逐渐提高，并借助X衍射和SEM手段对复合材料的组成和显微结构进行了分析，讨论了工艺因素对材料氧化性能产生影响的机理。     

Effects of MgO content and CaO/Al_2O_3 ratio on surface tension of calcium aluminate refining slag

Surface tension of calcium aluminate refining slag was measured by the Slide method at 1823 K.Based on different levels of the MgO content and the mass ratio of CaO to Al_2O_3,the effects of MgO content and the mass ratio of CaO to Al_2O_3 on surface tension were investigated.The results indicate that surface tension decreased with increasing MgO content(from 0 to 4.86%),followed by an increase with further increasing MgO content up to 11.33%.The trend that surface tension changed with the mass ratio of CaO to Al_2O_3 was the same as the trend that surface tension changed with the MgO content.The surface tension was varied from 0.617 N/m to 0.710 N/m,for the mass ratio of CaO to Al_2O_3 varying between 0.60 and 1.28.An attempt was made to estimate surface tension of CaO-Al_2O_3-MgO slag and its sub-system,and the application showed that the model worked well.     

SO_4~(2-)/TiO_2-ZrO_2-Nd_2O_3催化剂的制备及其催化合成双季戊四醇六脂肪酸酯

用共沉淀和浸渍法制备SO24-/TiO2-ZrO2-Nd2O3三元超强酸,以其为催化剂,合成双季戊四醇六辛酸酯,考察了钕(Nd)的质量分数、焙烧时间、焙烧温度对三元超强酸催化性能的影响;同时采用正交试验对制备条件进行了优化。催化剂用BET、SEM、XRD、FTIR表征,双季戊四醇六辛酸酯的结构采用FTIR表征。结果表明,加入Nd使固体酸体积变大,酸性增强,550℃时超强酸中的TiO2由无定型结构变为锐钛矿晶型结构,SO24-/TiO2-ZrO2-Nd2O3的最佳制备条件是Nd质量分数为1.5%,焙烧温度550℃,焙烧时间4h,其酯化率达92.3%。FTIR表征结果认证了产品为双季戊四醇六辛酸酯。     

以TiB2作为硼源制备硼酸铝晶须的合成机理

以TiB2作为硼源制备了硼酸铝晶须，对反应过程中的相转变以及晶须的生长机理进行了分析。结果表明，（NH4）2SO4分解释放活性[O]使TiB2氧化生成B2O3，为硼酸铝晶须的生长提供硼源。砧／B的配比对晶须的形态影响较大。在晶须的生长过程中，过量的液态B2O3作为一个载体可以把Al2O3输运到晶核的附近促进晶须的生长。     

Effect of Al_2O_(3np) on the Properties and Microstructure of B_4C_p/Al Composites

Aluminum-matrix boron carbide (B_4C_p/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage.In order to improve the tensile property of B_4C_p/Al composites,a new type of nano-Al_2O_3 particle (Al_2O_(3np)) reinforced B_4C_p/Al + Al_2O_(3np) composites were prepared by powder metallurgy method.The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al_2O_(3np )on the thermal neutron absorptivity of composites.The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties,microstructure and fracture morphology of B_4C_p/Al composites.The results indicated that the neutron absorption properties of B_4C_p/Al composites were not affected by the addition of nano-Al_2O_3 particles in the range of 1 wt%-15 wt%.The addition of Al_2O_(3np) can obviously reduce the grain size of B_4C_p/Al matrix metals thus improve the tensile strength of the composites.The addition threshold of Al_2O_(3np) is about 2.5 wt%.Both B_4C_p and Al_2O_(3np) change the fracture characteristics of the composites from toughness to brittleness,and the latter is more important.     

Sol-gel法制备Al2O3复合膜的EPMA研究

研究采用Sol—gel法成功地制备了一种新型的A12O3—SiO2-TiO2-ZrO2复合陶瓷膜，其膜面平整，无宏观缺陷。利用电子探针微区分析(EPMA)重点研究了膜的表面和膜与基体界面的化学成分及微观结构。并分析了修饰物添加剂对膜的形貌和性能的影响。结果表明TiO2、SiO2、ZrO2掺杂对A12O3膜起到了良好的修饰作用。     

溶胶-凝胶法制备无机纳米杂化聚酰亚胺薄膜

通过溶胶-凝胶法合成纳米二氧化硅及氧化铝溶胶,将其掺入聚酰胺酸基体中,制得二氧化硅-氧化铝／聚酰亚胺纳米杂化薄膜,利用红外光谱、扫描电子显微镜及热失重法对薄膜的结构、微观形貌及热性能进行表征．结果表明,薄膜材料中SiO2和Al203粒子分散均匀,与有机相存在键合;材料热分解温度有所提高．     

Preparation and Performance of Hollow Spherical Li_4Ti_5O_(12) Doped by Mg~(2+)

The microstructure and performance of Li_4Ti_5O_(12) doped by Mg prepared by hydrothermal method and solid phase method were investigated. Lithium dihydrate, magnesium acetate and tetrabutyl titanate were used as the main raw materials. This study reveals that Mg~(2+) has influences on the spherical structure, crystal development of Li_4Ti_5O_(12) and the electrochemical performances. The hollow spherical structure is composed of nano-sheet structure and the nano-sheet structure can be affected by the Mg~(2+) content. For Li4-xMgxTi5 O12, the sheet structure can be refined with the increment of Mg~(2+) content when x value is 0-0.1 and coarsen with the increment of Mg~(2+) content when x value is 0.1-0.2. The hollow spherical Li_4Ti_5O_(12) powders prepared by hydrothermal method have better performance. The optimal Mgdoped amount of hydrothermal method is 0.1. At 0.1 C, the first discharge capacity of Li_(3.9)Mg_(0.1)Ti_5O_(12) prepared through hydrothermal method at 0.1 C and 10 cycles is 182 and 178 m A h g~(-1), respectively.     

包覆法添加烧结助剂制备A12O3/SiCp复相陶瓷

通过包覆的方法将烧结助剂Y2 O3均匀地加入到陶瓷粉体中 ,用无压烧结制备Al2 O3-SiCp 复相陶瓷材料。在Al2 O3 SiC混合粉体上覆一层Y (OH) 3后 ,素坯结构均匀 ,且有利于提高素坯致密性。在较佳条件下 ,材料的相对密度和强度分别达到96 8%和 364MPa。     

负载型纳米ZrO2/Al2O3复合载体的制备与表征

以大孔Al2O3为基载体，用沉积-沉淀法和溶胶-凝胶法分别制备负载型纳米ZrO2／Al2O3复合载体，利用X射线衍射(XRD)、透射电子显微镜(TEM)、比表面与孔径测定仪等对载体和催化剂进行了表征．结果表明，负载型纳米ZrO2／Al2O3复合载体具有较大的比表面积和适宜的孔径分布，ZrO2第二载体在基载体上分布较均匀，粒径分别为19和15nm，复合载体的比表面积分别为101．6和113．5m^2／g．     

Fe3+-TiO2/SiO2气相光催化降解乙醛反应动力学研究

用浸渍法制备了Fe^3 -TiO2／SiO2负载型光催化剂,并进行了光催化降解气相中乙醛的实验和动力学研究．结果表明,Fe^3 掺杂量(nFe3 ／nTi4)为0．5％时光催化降解乙醛的效率最高;水气的存在提高了Fe^3 -TiO2／SiO2负载型催化剂的光催化活性,但使Fe^3 -TiO2纳米粉的光催化活性降低;O2的存在使Fe^3 -TiO2纳米粉和Fe^3 -TiO2／SiO2负载型催化剂的催化活性均有所降低;光强减弱使乙醛降解率下降,反应速率与光强之间呈近似线性关系;光催化降解气相中乙醛的动力学可以用Langrauir-Hinshelwood动力学方程描述．