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Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
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Atomic structures and oxygen dynamics of CeO2 grain boundaries
Bin Feng1, Issei Sugiyama1, Hajime Hojo2
1Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan.
Scientific Reports
|February 4, 2016
Summary
Oxygen vacancies at grain boundaries in ceria (CeO2) impact oxygen dynamics and reactivity. This atomic-level understanding is key for developing advanced solid oxide fuel cells.
Area of Science:
- Materials Science
- Surface Chemistry
- Electrochemistry
Background:
- Grain boundaries (GBs) significantly influence material properties due to structural and chemical variations.
- Ceria (CeO2) is a critical material in solid oxide fuel cells (SOFCs), with GBs playing a vital role.
Purpose of the Study:
- To provide direct atomic-scale evidence of how oxygen vacancies at GBs affect local surface oxygen dynamics in CeO2.
- To correlate GB structure, oxygen vacancy concentration, and electrochemical activity.
Main Methods:
- Atomic-scale electron microscopy to determine GB atomic structures and oxygen vacancy concentrations.
- Theoretical calculations to complement experimental findings.
- Electrochemical strain microscopy to measure local GB oxygen reduction reactivity.
Main Results:
- Direct atomic-scale evidence shows oxygen vacancies in CeO2 grain boundaries modify local oxygen dynamics.
- GB electrochemical activities are directly influenced by oxygen vacancy concentrations.
- Oxygen vacancy concentrations are determined by local structural distortions within the GB core.
Conclusions:
- Understanding GB properties at the atomic scale is crucial for material performance.
- These findings offer new strategies for designing high-performance electrochemical devices like SOFCs.
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