Ceria (CeO 2 ) is an effective precious-metal-free catalyst that combusts PM (particulate matter), due to its ability to switch between Ce 4+ and Ce 3+ . In this work, to improve the activity of a ceria-based catalyst, cerium-praseodymium mixed oxide catalysts with various Ce−Pr ratios were synthesized with nanofiber morphologies, characterized, and compared with ceria catalysts. Two factors were considered: morphology and Ce−Pr ratio, which result in synergistic effects. In the ceria catalyst, we confirmed that a fibrous morphology is more advantageous for PM oxidation compared to nanocubes and nanorods with cubes, even though these samples have larger surface areas. In addition, the incorporation of Pr into the ceria nanofiber catalyst enhanced its intrinsic properties by promoting the reducibility and formation of oxygen vacancies. The analysis showed improved oxygen storage and supply capacity, especially for oxygen that is chemically adsorbed on the catalytic surface. PM oxidation tests demonstrated the Ce 0.5 Pr 0.5 O 2 -NF catalyst showed the best activity in air, which was consistent with the characterization results. Thus, the Ce 0.5 Pr 0.5 O 2 -NF sample was shown to be an effective and promising catalyst for PM oxidation.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2016R1 A5 A1009592).
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- Ce−Pr mixed oxide
- oxygen storage capacity
- oxygen vacancies
- soot oxidation
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry