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NO2 adsorption on Fe- and Cu-zeolite catalysts: The effect of the catalyst red–ox state

Paper ID Volume ID Publish Year Pages File Format Full-Text
46492 46440 2012 12 PDF Available
Title
NO2 adsorption on Fe- and Cu-zeolite catalysts: The effect of the catalyst red–ox state
Abstract

In the present work we investigate the adsorption of NO2 onto a Fe- and a Cu-promoted zeolite SCR catalyst in the absence of gaseous water, with a particular focus on the effect of the catalyst red–ox state. For both catalytic systems, results from the analysis of the gas phase during step changes of the NO2 concentration, combined with literature FTIR information, emphasize an important role of the catalyst red–ox state in the dynamics of NO2 adsorption: the molar ratio of released NO to adsorbed NO2 is close to 1/3 in the case of oxidized catalysts, in line with a two-steps mechanism leading to the formation of surface nitrates, but is greater when the catalyst is partially reduced. Furthermore the initial catalyst red–ox state influences the amount of nitrates that can be adsorbed on the catalyst surface, the pre-reduced sample exhibiting a greater storage capacity. The Cu-zeolite catalysts are able to store a greater amount of nitrates and are more easily reduced in comparison with the Fe-zeolite.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Fe-zeolite: dynamics of NO2 adsorption influenced by the initial catalyst red–ox state. ► Oxidized sample: three moles of NO2 consumed for one mole of NO released. ► Reduced sample: significantly higher NO evolution during NO2 adsorption. ► The same qualitative results obtained also over a Cu-zeolite catalyst. ► NO2 first oxidizes the catalyst, then formation of nitrates occurs.

Keywords
Adsorption; Diesel exhaust aftertreatment; Nitrogen oxides; Urea SCR; Zeolite catalysts
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NO2 adsorption on Fe- and Cu-zeolite catalysts: The effect of the catalyst red–ox state
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 111–112, 12 January 2012, Pages 433–444
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