Identification of local structure inducing proton conduction by in situ X-ray absorption spectroscopy

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01694
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: Kyushu University
• Principal Investigator: Yamazaki Yoshihiro 九州大学, 稲盛フロンティア研究センター, 教授 (30292246)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: プロトン伝導性酸化物 / 水和反応

Outline of Final Research Achievements

Hydration is the key reaction to incorporate protons by filling the oxygen vacancies, Vo, with hydroxyl groups and activate proton conduction in the perovskite. Probing the local environment of oxygen vacancies that are responsible for hydration is, however, challenging because hydration depends on temperature and water partial pressure, which necessitates in situ observation and calculations of the local environment at high temperatures. It is found that the oxygen vacancies preferably exist in the vicinity of Sc dopant as the Sc-VO-Sc and Sc-VO-Zr environments and the former contributes most to hydration in the perovskite. The Zr-Vo-Zr environment is the least abundant among local oxygen vacancy environments in the whole temperature range examined, thus having negligible impact on hydration.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

これまで困難であった酸化物の水和挙動のその場観察、特に固体に存在する酸素空孔周りの局所構造変化のその場観察に世界で初めて成功した。これにより、酸化物にプロトン伝導を誘起するのに必要不可欠な水和反応と局所構造の関係性が明らかにされた。