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Light alkane dehydrogenation over mesoporous Cr2O3/Al2O3 catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
41892 45903 2010 10 PDF Available
Title
Light alkane dehydrogenation over mesoporous Cr2O3/Al2O3 catalysts
Abstract

Light alkane dehydrogenation was investigated over a series of mesoporous Cr2O3/Al2O3 catalysts containing 2–15 wt.% chromia, synthesized via the supramolecular templating technique. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR), UV–vis (ultra violet visible), X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). Depending on chromia loading, chromium was found to be present essentially as two surface species, each possessing one short terminal CrO bond and polymeric species. UV–vis and XPS studies revealed that the surface chromium occurs in two chemical states as Cr(III) and Cr(VI) species. Investigation of ethane and propane adsorption by in situ diffuse reflectance FTIR spectroscopy (DRIFT) revealed the formation of adsorbed acetaldehyde, acetone, formate and acetate. During the dehydrogenation reaction, acetate/carboxylate and hydrocarbon species were detected. Under otherwise the same conditions, the alkane dehydrogenation activity increased with increasing chromia loading. The activity of regenerated catalysts was found to be lower than the corresponding fresh catalysts, suggesting that the deactivation is partly permanent. Detailed characterization studies of spent and regenerated catalysts indicated that the formation of subsurface Cr(III) species during dehydrogenation may be the reason for the permanently lost activity.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (35 K)Download as PowerPoint slideResearch highlights▶ Novel mesoporous Cr2O3/Al2O3 were synthesis and tested for light alkane dehydrogenation. ▶ XPS studies revealed that surface chromium occurs in two chemical states as Cr(III) and Cr(VI). ▶ Characterization of spent and regenerated catalysts indicated that the formation of subsurface Cr(III) species during dehydrogenation may be the reason for partial irreversible loss of activity.

Keywords
Chromia-alumina; Alkane dehydrogenation; Catalyst deactivation; Diffuse reflectance Fourier transform infrared spectroscopy (DRIFT); Raman; X-ray photoelectron spectroscopy (XPS); UV–vis (ultra violet visible)
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 389, Issues 1–2, 1 December 2010, Pages 155–164
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