物理化学学报 >> 2005, Vol. 21 >> Issue (09): 1011-1016.doi: 10.3866/PKU.WHXB20050914

研究论文 上一篇    下一篇

MgO-ZrO2共沉淀体系的结构表征及单层分散现象

管洪波; 梁健; 朱月香; 赵璧英; 谢有畅   

  1. 北京大学化学与分子工程学院, 物理化学研究所, 分子动态与稳态结构国家重点实验室, 北京 100871
  • 收稿日期:2005-01-21 修回日期:2005-03-25 发布日期:2005-09-15
  • 通讯作者: 朱月香 E-mail:zhuyx@pku.edu.cn

Structure Characterization and Monolayer Dispersion Phenomenon of MgO-ZrO2 Prepared by Co-precipitation

GUAN Hong-bo; LIANG Jian; ZHU Yue-xiang; ZHAO Bi-ying; XIE You-chang   

  1. State Key Laboratory for Structural Chemistry of Unstable & Stable Species, Institute of Physical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871
  • Received:2005-01-21 Revised:2005-03-25 Published:2005-09-15
  • Contact: ZHU Yue-xiang E-mail:zhuyx@pku.edu.cn

摘要: 用共沉淀法制备了一系列MgO-ZrO2复合氧化物, 用XRD、XPS、BET、DTA、EXAFS和TEM等进行了表征. 结果表明, 500 ℃与600 ℃下焙烧得到的MgO-ZrO2复合氧化物, 在ZrO2高含量一端, MgO倾向于固溶到ZrO2中, 最大固溶量可达到1:1(摩尔比);固溶达到饱和后, MgO开始在固溶体表面分散, 并析出单独的MgO晶粒;在MgO高含量端, 少量的ZrO2以分散态存在于MgO的表面, 并使其表面性质发生较明显的变化. 这些结果表明, 在共沉淀法制备的MgO-ZrO2样品中, 在一定相对含量范围内, 会出现一种组分在另一种组分或由两种组分形成的固溶体上的单层分散现象.

关键词: ZrO2, MgO, 二元氧化物, 单层分散, 共沉淀, 固溶体

Abstract: A series of MgO-ZrO2 composites with various compositions were prepared by co-precipitation with NH4OH from mixed aqueous solution of nitrates and calcination at 500 ℃ and 600 ℃ respectively. The samples were characterized by XRD, XPS, BET, TEM, EXAFS and DTA measurements. The results exhibit that MgO tends to dissolve into the bulk phase of ZrO2 to form solid solution as Mg/Zr molar ratio is lower than 1. After the dissolution reaches saturation, MgO starts to disperse onto the surface of the solid solution, and at the same time the separate crystalline phase of MgO appears. However, when the content of MgO is high, ZrO2 does not dissolve into the bulk phase of MgO and not form the separate crystalline phase of ZrO2, but disperses onto the surface of the crystallite of MgO. And the properties of the surfaces of the samples were obviously affected by the dispersion of ZrO2. These results suggest that in the samples prepared by co-precipitation, one component can disperse as a monolayer onto the surface of the separate crystalline phase of the other component or the solid solutions composed of the two components in a certain content range. This phenomenon might exist in many binary oxide systems and deserves much more attention.

Key words: ZrO2, MgO, Binary oxide, Monolayer dispersion, Co-precipitation, Solid solution