This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Investigation on NOx Storage Characteristics and Aging Influence of Lean NOx Trap Model Catalyst BaO-Pt/Al2O3
Technical Paper
2010-01-0364
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Barium oxide (BaO) and platinum (Pt) are the key components in lean NOx trap (LNT) catalysts. Previous work has demonstrated that highly dispersed and bulk-like BaO species have low-temperature (LT) and high-temperature (HT) release features for stored nitrogen dioxide (NO₂). To better understand the roles of both BaO and Pt, a series of BaO/Al₂O₃ and BaO-Pt/Al₂O₃ were prepared and used to investigate the release characteristics of stored NO₂. Two typical BaO-Pt/Al₂O₃ catalysts having 75% and 44% of dispersed BaO, respectively, were aged and used for both the static NO₂ storage and the dynamic NOx elimination by lean-rich cyclic reactions. Results showed that bulk-like BaO plays a lesser role in storing NO₂ than does dispersed BaO. Pt inhibits the formation of nitrates and thus decreases NO₂ storage capacity (NSC) as Pt can catalyze the release, particularly for NO₂ species stored on bulk-like BaO. Aging in the range of 750-950°C resulted in a decrease of NSC but the HT release peak was restored with release features similar to those for NO₂ stored on BaO/Al₂O₃, indicating that the Pt inhibiting role weakens on the formation of nitrate over aged BaO-Pt/Al₂O₃. Lean-rich cyclic reactions have shown that the BaO-Pt/Al₂O₃ catalyst that was aged at 950°C totally lost the ability to eliminate NOx in the range of 250-600°C in the lean cycles due to Pt sintering. These Pt crystallites were still able to catalyze the lean cycle's oxidation of NO to NO₂ and the rich cycle's reduction of NO, suggesting that the sintered Pt particles significantly decreased the spillover ability of NOx from Pt to BaO species.
Recommended Content
| Technical Paper | The Pt-Ba Interaction in Lean NOx Trap Systems |
| Technical Paper | Rapid Aging of Diesel Lean NOx Traps by High-Temperature Thermal Cycling |
| Technical Paper | Analysis of Storage and Reaction Phases of LNT for Diesel Engine Exhaust Treatment |
Authors
Topic
Citation
Chen, X. and Schwank, J., "Investigation on NOx Storage Characteristics and Aging Influence of Lean NOx Trap Model Catalyst BaO-Pt/Al2O3," SAE Technical Paper 2010-01-0364, 2010, https://doi.org/10.4271/2010-01-0364.Also In
References
- Chen X. Schwank J. Li J. Schneider W.F. Goralski C.T. Jr. Schmitz P.J. “A Thermogravimetric Determination of Dispersed and Bulk-Like Barium Species Supported on γ-alumina” J. Mater. Chem. 15 2005 366
- Szanyi J. Kwak J.H. Hanson J. Wang C. Szailer T. Peden C.H.F. “Changing Morphology of BaO/Al 2 O 3 : during NO 2 Uptake and Release” J. Phys. Chem. 109 2005 7339
- Chen X. Schwank J. Li J. Schneider W.F. Goralski C.T. Jr. Schmitz P.J. “Thermal Decomposition of Dispersed and Bulk-Like NO x Species in Model NO x Trap Materials” Appl. Catal. B: Environ. 61 2005 189
- Szanyi J. Kwak J.H. Kim D.H. Burton S.D. Peden C.H.F. “NO 2 Adsorption on BaO/Al 2 O 3 : the Nature of Nitrate Species” J. Phys. Chem. 109 2005 27
- Clayton R.D. Harold M.P. Balakotaiah V. Wan C.Z. “Pt Dispersion Effects during NO x Storage and Reduction on Pt/BaO/Al 2 O 3 Catalysts” Appl. Catal. B: Environ. 90 2009 662
- Cant N.W. Liu I.O.Y. Patterson M.J. “The Effect of Proximity Between Pt and BaO on Uptake, Release, and Reduction of NO x on Storage Catalysts” J. Catal. 243 2006 309
- Nova, I. Castoldi, L. Lietti, L. Tronconi, E. et al. “The Pt-Ba Interaction in Lean NO x Trap Systems,” SAE Technical Paper 2005-01-1085 2005
- Büchel R. Strobel R. Krumeich F. Baiker A. Pratsinis S.E. “Influence of Pt Location on BaCO 3 or Al 2 O 3 during NO x Storage Reduction” J. Catal. 261 2009 201
- Chen X. Schwank J. “Steam Effect on NO x Reduction over Lean NO x Trap Pt-BaO/Al 2 O 3 Model Catalyst” Topics Catal. 46 2007 39
- Zhou G. Luo T. Gorte R.J. “An Investigation of NO x Storage on Pt-BaO-Al 2 O 3 ” Appl. Catal. B: Environ. 64 2006 88
- Cant N.W. Patterson M.J. “The Storage of Nitrogen Oxides on Alumina-Supported Barium Oxide” Catal. Today 73 2002 271
- Nova I. Castoldi L. Lietti L. Tronconi E. Forzatti P. Prinetto F. Ghiotti G. “NO x Adsorption Study over Pt-Ba/Alumina Catalysts: FT-IR and Pulse Experiments” J. Catal. 222 2004 377