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Investigation of the Defect-Chemistry of Ceria-Zirconia Mixed Oxides (CZO) Using Microwaves

Title data

Steiner, Carsten ; Kogut, Iuri ; Hagen, Gunter ; Fritze, Holger ; Moos, Ralf:
Investigation of the Defect-Chemistry of Ceria-Zirconia Mixed Oxides (CZO) Using Microwaves.
Event: PACRIM 14, The 14th Pacific Rim Conference of Ceramic Societies , 13.12.-16.12.2021 , Vancouver (virtual), USA.
(Conference item: Conference , Speech )

Abstract in another language

Ceria-zirconia mixed oxides (CZO) are oxygen storage materials. They are an elementary part of three-way catalysts (TWC) in modern gasoline vehicles. Previous studies showed that the oxygen storage level of a TWC can be operando determined using microwave technology. To investigate the dielectric behavior of CZO under microwave conditions in more detail, Ce1-xZrxO2-δ powders were studied in a microwave resonator specifically designed for high temperatures in a wide oxygen partial pressure (pO2) range. Dielectric properties of the CZO powders were analyzed between pO2≈ 10-25 bar and pO2≈ 0.2 bar at 600 °C. Under oxidizing conditions, a lower pO2 led to an increase in conductivity, which is likely related to an activated small-polaron hopping mechanism due to oxygen vacancy formation. Under reducing conditions, only small changes in conductivity were observed, which is probably attributed to a suppression of the hopping mechanism by higher non-stoichiometries δ ([Ce3+] ≈ [Ce4+]). Additionally, comparison with data of pure ceria suggests that the formation of oxygen vacancies in CZO is hardly dependent on the microstructure. The results of the study provide further insight into CZO and may contribute to better understand the defect chemistry of CZO and to improve the control of three-way catalysts using microwave technology.

Further data

Item Type: Conference item (Speech)
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
Faculties > Faculty of Engineering Science > Chair Functional Materials
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 21 Dec 2021 08:32
Last Modified: 21 Dec 2021 08:32