中国物理B ›› 2022, Vol. 31 ›› Issue (10): 107102-107102.doi: 10.1088/1674-1056/ac7457

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Origin of the low formation energy of oxygen vacancies in CeO2

Han Xu(许涵)1,2, Tongtong Shang(尚彤彤)1,2,‡, Xuefeng Wang(王雪锋)1,2, Ang Gao(高昂)1,2, and Lin Gu(谷林)1,2,3,†   

  1. 1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Songshan Lake Materials Laboratory, Dongguan 523808, China
  • 收稿日期:2022-04-17 修回日期:2022-05-21 出版日期:2022-10-16 发布日期:2022-09-16
  • 通讯作者: Lin Gu, Tongtong Shang E-mail:l.gu@iphy.ac.cn;shangtt@iphy.ac.cn
  • 基金资助:
    This work was supported by the Beijing Natural Science Foundation (Grant No. Z190010), the National Key R&D Program of China (Grant No. 2019YFA0308500), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07030200), the Key Research Projects of Frontier Science of Chinese Academy of Sciences (Grant No. QYZDB-SSW-JSC035), and the National Natural Science Foundation of China (Grant Nos. 51421002, 51672307, 51991344, and 52025025).

Origin of the low formation energy of oxygen vacancies in CeO2

Han Xu(许涵)1,2, Tongtong Shang(尚彤彤)1,2,‡, Xuefeng Wang(王雪锋)1,2, Ang Gao(高昂)1,2, and Lin Gu(谷林)1,2,3,†   

  1. 1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Songshan Lake Materials Laboratory, Dongguan 523808, China
  • Received:2022-04-17 Revised:2022-05-21 Online:2022-10-16 Published:2022-09-16
  • Contact: Lin Gu, Tongtong Shang E-mail:l.gu@iphy.ac.cn;shangtt@iphy.ac.cn
  • Supported by:
    This work was supported by the Beijing Natural Science Foundation (Grant No. Z190010), the National Key R&D Program of China (Grant No. 2019YFA0308500), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07030200), the Key Research Projects of Frontier Science of Chinese Academy of Sciences (Grant No. QYZDB-SSW-JSC035), and the National Natural Science Foundation of China (Grant Nos. 51421002, 51672307, 51991344, and 52025025).

摘要: Oxygen vacancies play a crucial role in determining the catalytic properties of Ce-based catalysts, especially in oxidation reactions. The design of catalytic activity requires keen insight into oxygen vacancy formation mechanisms. In this work, we investigate the origin of oxygen vacancies in CeO2 from the perspective of electron density {via} high-energy synchrotron powder x-ray diffraction. Multipole refinement results indicate that there is no obvious hybridization between bonded Ce and O atoms in CeO2. Subsequent quantitative topological analysis of the experimental total electron density reveals the closed-shell interaction behavior of the Ce—O bond. The results of first-principles calculation indicate that the oxygen vacancy formation energy of CeO2 is the lowest among three commonly used redox catalysts. These findings indicate the relatively weak bond strength of the Ce—O bond, which induces a low oxygen vacancy formation energy for CeO2 and thus promotes CeO2 as a superior catalyst for oxidation reactions. This work provides a new direction for design of functional metal oxides with high oxygen vacancy concentrations.

关键词: CeO2, oxygen vacancy, synchrotron x-ray diffraction, electron-density distribution

Abstract: Oxygen vacancies play a crucial role in determining the catalytic properties of Ce-based catalysts, especially in oxidation reactions. The design of catalytic activity requires keen insight into oxygen vacancy formation mechanisms. In this work, we investigate the origin of oxygen vacancies in CeO2 from the perspective of electron density {via} high-energy synchrotron powder x-ray diffraction. Multipole refinement results indicate that there is no obvious hybridization between bonded Ce and O atoms in CeO2. Subsequent quantitative topological analysis of the experimental total electron density reveals the closed-shell interaction behavior of the Ce—O bond. The results of first-principles calculation indicate that the oxygen vacancy formation energy of CeO2 is the lowest among three commonly used redox catalysts. These findings indicate the relatively weak bond strength of the Ce—O bond, which induces a low oxygen vacancy formation energy for CeO2 and thus promotes CeO2 as a superior catalyst for oxidation reactions. This work provides a new direction for design of functional metal oxides with high oxygen vacancy concentrations.

Key words: CeO2, oxygen vacancy, synchrotron x-ray diffraction, electron-density distribution

中图分类号:  (Rare earth metals and alloys)

  • 71.20.Eh
61.72.jd (Vacancies) 61.05.cp (X-ray diffraction) 71.20.-b (Electron density of states and band structure of crystalline solids)