Shuigen HUANG
,
Lin LI
,
O.V.D.Biest
,
J.Vleugels
,
Peiling WANG
材料科学技术（英文）
Using compound energy model (CEM), the thermodynamic properties of and were evaluated. The evaluation was based on the optimization of ZrO2-CeO2 and ZrO2-CeO1.5 systems, as well as the miscibility gap in CeO1.5-CeO2 system. Except the cubic fluorite structure phase assessed with compound energy model, all the other solution phases were assessed with subsitutional solution model. The model parameters were evaluated through fitting the selected experimental data by means of thermodynamic optimization. A set of parameters with thermodynamics self-consistency was obtained and satisfactorily described the complex relation between y in and the partial pressure of oxygen at different temperatures, also the interdependence among miscellaneous factors such as temperature, oxygen partial pressure, the reduction amount of CeO2 as well as the nonstoichiometry in cubic phase . The calculated results seem to be reasonable when put into the explanation of pressureless sintering of CeO2-stabilized ZrO2 powder compacts at a controlled oxygen partial pressure.
关键词:
Zirconia
,
null
,
null
,
null
Xiaoli WANG
,
Lucun GUO
材料科学技术（英文）
The relationship between processing route and suspension stability in ZrO2-H2O-PANH4 system was investigated through rheology study. The work showed that two suspensions with identical PANH4 concentration and final solution condition but prepared by different routes differed greatly in stability. This behavior is attributed to their different distribution state of PANH4 on ZrO2 surface that is determined by the adsorption affinity depending on pH condition in solution. High affinity at pH 5.0 induces a nonuniform distribution of soluble PAA－ (polyacrylicacid) on particle surface, which can flocculate the suspension strongly, while low affinity at pH 9.0 induces an uniform distribution of polymer so that the higher stabilization can be achieved. A simple mathematical model was used to account for the observed results.
关键词:
Zirconia
,
制备途径
,
稳定性
,
流变性
王铭浩
,
苏宏久
,
周谨
,
王树东
催化学报
doi:10.1016/S1872-2067(12)60609-3
使用浸涂法和氨气吸收沉积法制备了新型用于苯选择加氢的具有蛋壳型分布的Ru/Al2O3-ZrO2-NiO/堇青石蜂窝整体催化剂,且在固定床整体反应器中对其性能进行了测试.该催化剂显示了较优的选择性和稳定性,并且在低的ZnSO4浓度(0.5％问题)下环己烯产物收率可达24.7％.采用N2吸附-脱附法,电感耦合等离子体发射光谱,光学显微镜,扫描电子显微镜及能量色散X射线光谱仪等技术研究了影响催化剂性能的因素.结果表明,NiO的引入减少了涂层中的微孔含量,有利于在低的添加剂浓度下提高环己烯选择性.ZrO2的存在抑制了涂层的烧结,保证涂层在1373K高温焙烧后仍有较大的比表面积.Ru的蛋壳分布、薄的涂层厚度、较少的微孔含量、较大的比表面积和狭窄的孔分布可能是影响整体蜂窝催化剂中该特殊催化行为的重要因素.
关键词:
整体催化剂
,
涂层
,
苯
,
环己烯
,
选择性加氢
,
尖晶石
,
氧化锆
,
氧化镍
Ying LI
,
Yunfa CHEN
,
Jianghong GONG
材料科学技术（英文）
The ac conductivities of Y2O3 or CaO-stabilized cubic zirconias were obtained from complex impedance measurements in the temperature range from 373 to 473 K. By analyzing the temperature-dependence of the resultant dc conductivities, it was shown that the activation energies for conduction are lower than those reported previously for the same materials at high temperatures. Comparing the activation energy data with the theoretically estimated values revealed that there may exist a certain, although very small, amount of free oxygen vacancies in the test samples at low temperatures and the conduction in the test samples is a result of the migration of these free oxygen vacancies.
关键词:
Ionic conductivity
,
null
,
null
,
null
尚书宁
,
徐欣
,
谢鹏飞
,
乐英红
,
华伟明
,
高滋
催化学报
doi:10.1016/S1872-2067(12)60540-3
采用恒pH法和非恒pH法制备了Al2O3掺杂的Pt/WO3/ZrO2催化剂,并用N2吸附-脱附、X射线衍射、紫外-可见漫反射、CO化学吸附、X射线光电子能谱、27Al魔角旋转核磁共振和吡啶吸附红外等技术对催化剂进行了表征.结果表明,相比于非恒pH法制备的催化剂,恒pH法制备的催化剂具有较高的比表面积和Pt分散度,在H2气氛中产生更多的B酸位,从而表现出更高的催化正庚烷临氢异构化反应活性;在200℃和质量空速0.9 h-1的反应条件下,正庚烷转化率达70.0％,明显高于非恒pH法制备的催化剂(43.5％).
关键词:
铂
,
氧化钨
,
氧化锆
,
氧化铝掺杂
,
制备方法
,
正庚烷临氢异构化
,
质子酸位
张兴华
,
张琦
,
陈伦刚
,
徐莹
,
王铁军
,
马隆龙
催化学报
doi:10.1016/S1872-2067(12)60733-5
采用化学沉淀法合成了SiO2-ZrO2复合氧化物载体，并以浸渍法制备了Ni/SiO2-ZrO2双功能催化剂，考察了焙烧温度对催化剂结构及其催化愈创木酚加氢脱氧制环己烷性能的影响.结果表明，经500°C焙烧催化剂的加氢脱氧活性最高，在Ni金属中心和SiO2-ZrO2载体材料的协同作用下，愈创木酚转化率为100%，环己烷选择性为96.8%.对催化剂进行N2物理吸附、H2化学吸附、X射线衍射分析、H2程序升温还原、NH3程序升温脱附与Raman光谱等表征后发现，合成的SiO2-ZrO2为无定形的酸碱两性氧化物；经500°C焙烧的催化剂样品的有效比表面积和孔体积均明显增大，表面酸量最多，硝酸镍分解成小颗粒的NiO较易被H2还原，这些特性是该催化剂样品具有高效加氢脱氧活性的原因.
关键词:
镍
,
氧化硅
,
氧化锆
,
焙烧温度
,
愈创木酚
,
加氢脱氧
,
环己烷
孙海杰
,
江厚兵
,
李帅辉
,
王红霞
,
潘雅洁
,
董英英
,
刘寿长
,
刘仲毅
催化学报
doi:10.1016/S1872-2067(11)60489-0
采用共沉淀法制备了一系列不同Mn含量的纳米Ru-Mn催化剂,考察了纳米ZrO2作分散剂时它们催化苯选择加氢制环己烯的反应性能,并采用X射线衍射、透射电镜、N2物理吸附、X射线荧光、原子吸收光谱和俄歇电子能谱等手段对催化剂进行了表征.结果表明,Ru-Mn催化剂上Mn以Mn3O4存在于Ru的表面上.在加氢过程中,Mn3O4可以与浆液中ZnSO4发生化学反应生成一种难溶性的(Zn(OH)2)3(ZnSO4)(H2O)3盐.该盐易化学吸附在Ru催化剂表面上,从而在提高Ru催化剂上环己烯选择性起关键作用.当催化剂中Mn含量为5.4％时,环己烯收率为61.3％,同时具有良好的稳定性和重复使用性能.
关键词:
苯
,
选择加氢
,
环己烯
,
钌
,
锰
,
二氧化锆
,
锌
钟亮
,
陈晓红
,
宋怀河
,
胡子君
,
孙陈诚
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.01.014
以硝酸氧锆为锆源,尿素为凝胶促进剂,通过水热凝胶法结合超临界乙醇干燥,可成功制备出具有良好纳米三维网络结构的ZrO2气凝胶.采用透射电镜(TEM)、比表面积及孔隙度分析仪(BET),X射线衍射仪等测试手段对其结构进行了表征与测试.结果表明,ZrO2气凝胶主要由无定型和四方晶相组成,其比表面积为445 m2/g,孔径主要分布在5～7 nm和30～40 nm两处.
关键词:
ZrO2
,
气凝胶
,
超临界干燥
,
比表面积
