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Modeling the effects of Pt loading on NOx storage on Pt/BaO/Al2O3 catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
46968 46454 2011 11 PDF Available
Title
Modeling the effects of Pt loading on NOx storage on Pt/BaO/Al2O3 catalysts
Abstract

Platinum plays an important, multi-functional role during NOx storage and reduction (NSR). Understanding and predicting the effect of Pt loading is essential to optimize the lean NOx trap. In this study, a microkinetic model is developed for NOx storage on a series of Pt/BaO/Al2O3 catalysts with a range of Pt loadings (0–3.7 wt.%). A classification of the Ba sites into two storage site populations, proximal and non-proximal (bulk), is presented. A simple model for estimating the capacities of the two Ba site populations using the Pt loading is used to explain trends in the storage of NO/O2 and NO2/O2. The model integrates existing literature models for NO2 storage on BaO/Al2O3, Pt-catalyzed NO oxidation to NO2, and spillover chemistry involving NO2. Wherever possible, simplifications in the model are made based on sensitivity analyses. Literature estimates of kinetic parameters are adjusted if estimates of spillover rate constants are not sufficient to predict the storage data. The dual-site model comprises proximal storage sites that participate in the spillover chemistry and non-proximal sites that involve NO2 that is generated by the Pt-catalyzed NO oxidation. The model shows reasonable agreement with the measured storage of NO and NO2 in O2 at 340 °C for a range of storage times and Pt loading. The model helps to elucidate the storage dynamics and the roles of Pt and should be useful for incorporation into a complete NOx storage and reduction model. Some further refinements to the model are discussed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Microkinetic model developed for storage of NO/O2 and NO2/O2 on Pt/BaO/Al2O3. ► Spillover chemistry at Pt/BaO interface essential to predict storage enhancement. ► Model captures key transient trends including effect of Pt loading.

Keywords
NOx; NOx storage; Diesel emissions; Platinum; Barium; Microkinetic model; Kinetics
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Modeling the effects of Pt loading on NOx storage on Pt/BaO/Al2O3 catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 104, Issues 3–4, 18 May 2011, Pages 305–315
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us