NOx storage and reduction properties of model ceria-based lean NOx trap catalysts

Chuan Shi, Yaying Ji, Uschi M. Graham, Gary Jacobs, Mark Crocker, Zhaoshun Zhang, Yu Wang, Todd J. Toops

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

Three kinds of model ceria-containing LNT catalysts, corresponding to Pt/Ba/CeO2, Pt/CeO2/Al2O3 and Pt/BaO/CeO2/Al2O3, were prepared for comparison with a standard LNT catalyst of the Pt/BaO/Al2O3 type. In these catalysts ceria functioned as a NOx storage component and/or a support material. The influence of ceria on the microstructure of the catalysts was investigated, in addition to the effect on NOx storage capacity, regeneration behavior and catalyst performance during lean/rich cycling. The Pt/Ba/CeO2 and Pt/BaO/CeO2/Al2O3 catalysts exhibited higher NOx storage capacity at 200 and 300°C relative to the Pt/BaO/Al2O3 catalyst, although the latter displayed better storage capacity at 400°C. Catalyst regeneration behavior at low temperature was also improved by the presence of ceria, as reflected by TPR measurements. These factors contributed to the superior NOx storage-reduction performance exhibited by the Pt/Ba/CeO2 and Pt/BaO/CeO2/Al2O3 catalysts under cycling conditions in the temperature range 200-300°C. Overall, Pt/BaO/CeO2/Al2O3 (which displayed well balanced NOx storage and regeneration behavior), showed the best performance, affording consistently high NOx conversion levels in the temperature range 200-400°C under lean-rich cycling conditions.

Original languageEnglish
Pages (from-to)183-196
Number of pages14
JournalApplied Catalysis B: Environmental
Volume119-120
DOIs
StatePublished - May 30 2012

Bibliographical note

Funding Information:
Rhodia is thanked for a gift of CeO 2 . This project was funded by the U.S. Department of Energy (DOE) under award No. DE-EE0000205.

Keywords

  • Barium
  • Ceria
  • Lean NO trap catalyst
  • Reduction
  • Storage

ASJC Scopus subject areas

  • Catalysis
  • General Environmental Science
  • Process Chemistry and Technology

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