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Effect of precious metals and NOx storage materials on hydrogen reduction of stored NOx on millisecond time scale

Paper ID Volume ID Publish Year Pages File Format Full-Text
40708 45863 2012 10 PDF Available
Title
Effect of precious metals and NOx storage materials on hydrogen reduction of stored NOx on millisecond time scale
Abstract

The effect of precious metals (PMs) and NOx storage materials (NSMs) on the reduction of stored NOx over PM/NSM/Al2O3 (PM = Pt, Rh, Pd; NSM = Ba, K, Na) catalysts was studied via transient reaction analysis using pulsed gases with submillisecond resolution. The time profiles of the product gases were analyzed with a high time resolution of 0.25 ms for the first 50 ms after supplying a hydrogen gas pulse.These results were explained with a model that correlates with the spillovers of released NOx species from the NSM and the activated hydrogen on the PM. The catalyst Pt/Na/Al2O3 had the highest reduction rate of stored NOx among the nine catalysts examined. This performance is due to both the lowest decomposition temperature of Na and the high reactivity of hydrogen on Pt. On the other hand, the Rh-containing catalysts exhibited a lower NH3 production capability than the Pt- and Pd-containing catalysts, and the Rh/K/Al2O3 catalyst had the least NH3 production capability and the lowest reduction rate of stored NOx. The lower NH3 production capability of Rh is caused both by the low hydrogen reactivity on Rh and the lowest reduction rate of stored NOx for Rh/K/Al2O3, which has the lowest surface area among the Rh-containing catalysts.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (221 K)Download as PowerPoint slideHighlights► High speed transient reaction analysis with submillisecond resolution. ► Effect of precious metals (Pt,Rh,Pd) and NOx storage materials (Ba,K,Na) was investigated on a regeneration reaction of stored NOx. ► This figure shows the case of Pt/Ba/Al2O3 catalyst.

Keywords
Time-of-flight mass spectrometry; Lean-burn engine; NOx storage-reduction catalyst; Platinum; Rhodium; Palladium; Barium; Potassium; Sodium
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Effect of precious metals and NOx storage materials on hydrogen reduction of stored NOx on millisecond time scale
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 445–446, 28 November 2012, Pages 133–142
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