Investigation of the Potential Energy Landscape for Vacancy Dynamics in Sc-Doped CeO2

详细信息    查看全文

• 作者：Sabyasachi Sen ; Trenton Edwards ; Seong K. Kim ; Sangtae Kim
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：March 11, 2014
• 年：2014
• 卷：26
• 期：5
• 页码：1918-1924
• 全文大小：377K
• 年卷期：v.26,no.5(March 11, 2014)
• ISSN：1520-5002

文摘

Here, we provide a comprehensive picture of the potential energy landscape (PEL) for oxygen-vacancy migration in Sc-doped ceria (SDC) based on the results from a combined application of ⁴⁵Sc and ¹⁷O nuclear magnetic resonance (NMR) and electrochemical impedance spectroscopy (EIS). The oxygen vacancies in SDC perform rapid symmetry-related jumps in the nearest-neighbor coordination shell of Sc traps as well as hopping from one Sc trap to another over length scales of a few nanometers. The activation energies for these two processes are determined to be 0.4 and 1.2 eV, respectively. The depths of these potential wells are modulated via high-frequency elastic deformation of the lattice, with a characteristic activation energy of 0.2 eV. The hopping of vacancies between Sc traps control the ionic conduction process in SDC, and the corresponding time scale is identical to the conductivity relaxation time scale.