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Sulfate storage and stability on representative commercial lean NOx trap components

Paper ID Volume ID Publish Year Pages File Format Full-Text
46366 46438 2012 10 PDF Available
Title
Sulfate storage and stability on representative commercial lean NOx trap components
Abstract

Components found in a commercial lean NOx trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl2O4, Pt/MgAl2O4, Pt/Al2O3, Pt/Ba/Al2O3, Pt/CeO2–ZrO2, and Pt/Ba/CeO2–ZrO2, as well as physical mixtures of Pt/Al2O3 + MgAl2O4 and Pt/Ba/CeO2–ZrO2 + MgAl2O4. Desulfation temperature profiles as well as DRIFTS NOx and SOx storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria–zirconia rather than alumina the desulfation temperature decreased by 60–120 °C. A conceptual model of sulfation progression on the ceria–zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlight► Supporting Ba on ceria–zirconia rather than alumina decreases the sulfate stability. ► Oxygen storage in ceria–zirconia impacts sulfur distribution during cycling. ► Pt proximal to sulfate sites not essential for sulfation or desulfation. ► MgAl2O4 can store sulfur in physical mixtures and may protect Ba-phase.

Keywords
Sulfur; Lean NOx trap; DRIFTS; Ceria–zirconia; MgAl2O4
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Sulfate storage and stability on representative commercial lean NOx trap components
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 117–118, 18 May 2012, Pages 167–176
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