NOx Storage and Reduction Properties of Model Ceria-based Lean NOx Trap Catalysts

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Applied Catalysis B

DOI:https://doi.org/10.1016/j.apcatb.2012.02.028· OSTI ID:1038809

Shi, Chuan ^[1]; Ji, Yaying ^[2]; Graham, Uschi ^[2]; Jacobs, Gary ^[2]; Crocker, Mark ^[2]; Zhang, Zhaoshun ^[1]; Wang, Yu ^[1]; Toops, Todd J ^[3]

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1. Dalian University
2. University of Kentucky
3. ORNL

Three kinds of model ceria-containing LNT catalysts, corresponding to Pt/Ba/CeO{sub 2}, Pt/CeO{sub 2}/Al{sub 2}O{sub 3} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3}, were prepared for comparison with a standard LNT catalyst of the Pt/BaO/Al{sub 2}O{sub 3} type. In these catalysts ceria functioned as a No{sub x} 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 No{sub x} storage capacity, regeneration behavior and catalyst performance during lean/rich cycling. The Pt/Ba/CeO{sub 2} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} catalysts exhibited higher No{sub x} storage capacity at 200 and 300 C relative to the Pt/BaO/Al{sub 2}O{sub 3} 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 No{sub x} storage-reduction performance exhibited by the Pt/Ba/CeO{sub 2} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} catalysts under cycling conditions in the temperature range 200-300 C. Overall, Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} (which displayed well balanced No{sub x} storage and regeneration behavior), showed the best performance, affording consistently high No{sub x} conversion levels in the temperature range 200-400 C under lean-rich cycling conditions.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1038809
• Journal Information: Applied Catalysis B, Vol. 119-120; ISSN 0926-3373
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CAPACITY
CATALYSTS
MICROSTRUCTURE
PERFORMANCE
REGENERATION
STORAGE