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Analysis of defect mechanisms in nonstoichiometric ceria-zirconia by the microwave cavity perturbation method

Title data

Steiner, Carsten ; Hagen, Gunter ; Kogut, Iurii ; Fritze, Holger ; Moos, Ralf:
Analysis of defect mechanisms in nonstoichiometric ceria-zirconia by the microwave cavity perturbation method.
In: Journal of the American Ceramic Society. Vol. 106 (2023) Issue 5 . - pp. 2875-2892.
ISSN 1551-2916

Official URL: Volltext

Project information

Project title:
Project's official title
Project's id
In-situ-Verfahren zur Bestimmung hoher Sauerstoffdefizite in Cer-Zirkon-Mischoxiden für den Einsatz in der Abgasnachbehandlung
MO 1060/29-1

Project financing: Deutsche Forschungsgemeinschaft

Abstract in another language

In this microwave study, the defect chemistry of ceria–zirconia solid solutions (CZO, Ce1−yZryO2−δ) was investigated at high temperatures by a resonant microwave method. Specifically, the effects of temperature and Zr content on the dielectric properties and defect chemistry mechanisms in CZO were analyzed. Experiments were performed on a series of different CZO powders (y = 0.2, 0.33, 0.50, 0.67). Measurements at 600°C and different oxygen partial pressures (pO2 = 10−26–0.2 bar) confirm a dominant n-type conduction of small-polarons in CZO due to the preferred formation of oxygen vacancies, which is also supported by a multimodal analysis. Polarization losses were found to be negligible in the GHz range. Furthermore, an increased relative permittivity was observed in CZO, which correlates with the concentration of oxygen vacancies in CZO. Our microwave study is the first to provide a comprehensive data set for the dielectric properties of CZO powder sample in a wide range of different conditions. In addition, the connection of dielectric properties to CZO defect chemistry mechanisms is presented. The results are in good agreement with findings in the literature and may contribute to a better understanding of microwave-based state diagnosis of CZO-based materials, as it discussed for three-way catalysts.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Research Institutions > Research Units > BERC - Bayreuth Engine Research Center
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 08 Mar 2023 07:44
Last Modified: 08 Mar 2023 07:44