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Effect of barium loading on CuOx–CeO2 catalysts: NOx storage capacity, NO oxidation ability and soot oxidation activity

Paper ID Volume ID Publish Year Pages File Format Full-Text
55731 47063 2011 9 PDF Available
Title
Effect of barium loading on CuOx–CeO2 catalysts: NOx storage capacity, NO oxidation ability and soot oxidation activity
Abstract

A series of Ba–Cu–Ce catalysts were prepared by loading different amounts of Ba(Ac)2 on the sol–gel-synthesized CuOx–CeO2 mixed oxides. The activities of the catalysts for soot oxidation were evaluated in 1000 ppm NO/10% O2/N2 under loose contact conditions. The catalysts were characterized by XRD, BET, H2-TPR, in situ-DRIFTS and NO-TPO measurements. When Ba loading is between 6 and 10 mol.% of Cu + Ce, the catalysts exhibit an onset temperature (Ti) as low as 376 °C. NO is oxidized at Cux+ and Cex+ sites and then stored on the adjacent Ba species in form of barium nitrate. Ba(NO3)3 begins to decompose, releasing abundant NO2 at around 370 °C under the driving of soot as the reductant. The nitrate-derived NO2 and the NO-derived NO2 initiate the soot combustion over the Ba-modified catalysts with a significantly lowered Ti. The ternary catalysts lose their NOx storage capacity after hydrothermally aged at 800 °C for 10 h due to the formation of BaCeO3. However, Ba restrains the sintering of (Cu,Ce)Ox, resulting in relatively more favorable redox properties and thus higher activity for NO oxidation. The barium-modified catalysts show lower onset temperatures (470–480 °C) of soot oxidation than pure CuCe (509 °C) after aging.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (166 K)Download as PowerPoint slideHighlights► The soot oxidation activity of CuOx–CeO2 catalyst in NOx is enhanced by loading Ba. ► The optimum loading amount of barium is 6–10 at.% of (Cu + Ce). ► The nitrate-derived NO2 assists the soot catalytic combustion. ► The NOx storage capacity deteriorates due to formation of BaCeO3 after aging. ► The loading of Ba restrains the sintering of CuO and CeO2 during hydrothermal aging.

Keywords
Cu–Ce mixed oxides; Barium loading; Soot oxidation; NO oxidation; NOx storage
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Effect of barium loading on CuOx–CeO2 catalysts: NOx storage capacity, NO oxidation ability and soot oxidation activity
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 175, Issue 1, 25 October 2011, Pages 124–132
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