烧绿石型富氧相Ce2Zr2O8的Rietveld结构精修及其Raman光谱研究

doi:10.3724/SP.J.1077.2014.13410

无机材料学报 ›› 2014, Vol. 29 ›› Issue (5): 539-544.DOI: 10.3724/SP.J.1077.2014.13410

烧绿石型富氧相Ce₂Zr₂O₈的Rietveld结构精修及其Raman光谱研究

谢华^1,2, 王烈林¹, 罗德礼²

(1. 西南科技大学核废物与环境安全国防重点学科实验室, 绵阳621010; 2. 表面物理与化学重点实验室, 绵阳 621907)

收稿日期:2013-08-12 修回日期:2013-10-25 出版日期:2014-05-20 网络出版日期:2014-04-24
作者简介:谢华(1979-), 女, 副研究员, 硕士研究生. E-mail: xiehua@swust.edu.cn
基金资助:
国家自然科学基金(21101129); 核废物与环境安全国防重点科学实验室开放基金(11zxnk08)

Rietveld Structure Refinement and Raman Spectroscopy of Pyrochlore-type Oxygen-rich Ce₂Zr₂O₈ Phase

XIE Hua^1,2, WANG Lie-Lin¹, LUO De-Li²

(1. Key Laboratory of Defensive Discipline on Nuclear Wastes and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010, China; 2. Key Laboratory of Surface physical and Chemistry, Mianyang 621907, China)

Received:2013-08-12 Revised:2013-10-25 Published:2014-05-20 Online:2014-04-24
About author:XIE Hua. E-mail: xiehua@swust.edu.cn
Supported by:
National Natural Science Foundation of China (21101129); Program of Key Laboratory of Defensive Discipline on Nuclear Wastes and Environmental Safety (11zxnk08)

摘要/Abstract

摘要： 采用石墨还原法成功制备了烧绿石型富氧相Ce₂Zr₂O₈, 选用缺氧型烧绿石Nd₂Zr₂O₇作为Ce₂Zr₂O₈相前驱体CeZrO_3.5的替代物与之进行结构对比分析。实验结果表明: Ce₂Zr₂O₈相中富余氧主要占据前驱体中的氧空位, 且氧离子扩散不会破坏原本有序排列的阳离子(Ce/Zr)亚点阵; 同时, Ce₂Zr₂O₈相中Zr-O 配位体由前驱体中共顶联接的八面体转变为共棱联接的立方体, 其反相畴界密度和振动光谱谱带亦较前驱体明显提高。以上结果说明Ce₂Zr₂O₈相结构处于亚稳态, 该结构特征有利于氧离子的快速吸附或释放, 这为其成为汽车尾气净化剂提供了结构上的可行性, 但也说明当An₂Zr₂O₇烧绿石在自辐照条件下向富氧相An₂Zr₂O₈发生转变时, 其抗辐照和化学稳定等性能有下降趋势。

关键词: Ce₂Zr₂O₈, 有序阳离子, 反相畴界, 配位体

Abstract: Pyrochlore-type oxygen-rich Ce₂Zr₂O₈ phase was prepared successfully by graphite reduction method. In order to compare the structure between Ce₂Zr₂O₈ and Nd₂Zr₂O₇, the pyrochlore Nd₂Zr₂O₇ was selected as the substitute of CeZrO_3.5+δ, the oxide precursor of Ce₂Zr₂O₈. Experimental results show that excessive oxygen in the Ce₂Zr₂O₈ structure mainly occupies the oxygen vacancies from the precursor structure. Oxygen ions diffusion in the precursor CeZrO_3.5 structure does not destroy the ordering cation sublattice. Meanwhile, Zr-O ligands are transformed from octahedrons of co-top connection in the precursor to cubes of co-edge connection in the Ce₂Zr₂O₈. The antiphase boundary density and Raman bands in comparison with?the precursor are improved significantly, suggesting the structure of Ce₂Zr₂O₈ phase is in a metastable state. The characteristic structure facililates rapid adsorption or release of oxygen ions, providing structural feasibility for ideal candidate materials for automobile exhaust purification. However, the structure of Ce₂Zr₂O₈ indicated that the radiation resistance and chemical stability may be downward when An₂Zr₂O₇ pyrochlore under self irradiation condition transforms to the oxygen-rich phase An₂Zr₂O₈.

Key words: Ce₂Zr₂O₈, ordering cations, antiphase domain boundary, ligands

中图分类号:

O731
TL93

谢华, 王烈林, 罗德礼. 烧绿石型富氧相Ce₂Zr₂O₈的Rietveld结构精修及其Raman光谱研究[J]. 无机材料学报, 2014, 29(5): 539-544.

XIE Hua, WANG Lie-Lin, LUO De-Li. Rietveld Structure Refinement and Raman Spectroscopy of Pyrochlore-type Oxygen-rich Ce₂Zr₂O₈ Phase[J]. Journal of Inorganic Materials, 2014, 29(5): 539-544.

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烧绿石型富氧相Ce₂Zr₂O₈的Rietveld结构精修及其Raman光谱研究

Rietveld Structure Refinement and Raman Spectroscopy of Pyrochlore-type Oxygen-rich Ce₂Zr₂O₈ Phase

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