Defect and Transport Model of Ceria鈥揨irconia Solid Solutions: Ce0.8Zr0.2O2鈭捨?/sub>鈥擜n Electrical Conductivity Study
详细信息 查看全文
- 作者：Di Chen ; Yidan Cao ; Duan Weng ; Harry L. Tuller
- 刊名：Chemistry of Materials
- 出版年：2014
- 出版时间：September 9, 2014
- 年：2014
- 卷：26
- 期：17
- 页码：5143-5150
- 全文大小：409K
- ISSN：1520-5002
文摘
The electrical conductivity (蟽) of Ce0.8Zr0.2O2鈭捨?/sub> was measured and modeled using a defect chemical-based model including contributions from singly and doubly ionized oxygen vacancies, acceptor impurities, and small polaron electrons. By analyzing the pO2 dependence of 蟽 in terms of the defect model, a transition between an impurity dominated regime at high pO2 and lower temperature to one controlled by the simultaneous generation of electrons and doubly ionized oxygen vacancies at low pO2 and higher temperature is identified. At even lower pO2, or equivalently larger deviations from stoichiometry, evidence is presented for a further transition to singly ionized oxygen vacancies accompanying electron generation. Temperature induced conductivity relaxation measurements are successfully applied in deconvoluting electron generation and migration contributions to the activation energy. Key parameters are extracted including the enthalpy of reduction Hr of 2.87 卤 0.06 eV and the electron hopping or migration energy of 0.354 卤 0.005 eV. Both the activated electron mobility and the broad maximum in conductivity observed under the most reducing conditions support the small polaron model for electron transport in Ce0.8Zr0.2O2鈭捨?/sub>. Consistent with earlier findings, Zr, though isovalent with Ce, markedly enhances the reducibility, and thereby the oxygen storage capability of ceria鈥搝irconia solid solutions.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |