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Oxidative dehydrogenation of propane over cobalt-containing mixed oxides obtained from LDH precursors

Paper ID Volume ID Publish Year Pages File Format Full-Text
41172 45879 2012 10 PDF Available
Title
Oxidative dehydrogenation of propane over cobalt-containing mixed oxides obtained from LDH precursors
Abstract

Co(x)MgAlO mixed oxide catalysts with cobalt content in the range from 1 to 20 at.%, were prepared by calcination of layered double hydroxide (LDH) precursors at 1023 K. Their characterization was performed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), N2 adsorption, Raman and photoluminescence spectroscopies, TG–DTG and H2-TPR techniques. The catalytic activities were evaluated in the oxidative dehydrogenation of propane in the temperature range from 723 to 873 K. For all the catalysts the conversion increased when the reaction temperature increased, while the propene selectivity decreased continuously to the benefit of COx for Co(20)MgAlO and Co(10)MgAlO catalysts and of cracking products for the other cobalt-containing catalysts. In all the temperature range studied, the catalytic activity increased with increasing the cobalt content in the catalyst in line with the increase of reducibility. The best yields in propene of about 10% were obtained with Co(5)MgAlO and Co(7)MgAlO catalysts for the reaction performed at 873 K. Besides, a comparison of the behavior of Co(3)MgAlO and Co(7)MgAlO catalysts at 823 K showed that, at isoconversion, the propene selectivity was higher for the sample with lower cobalt content. The well-dispersed cobalt species with tetrahedral coordination played a main role in the oxidative dehydrogenation reaction of propane into propene. When the propane-to-oxygen molar ratio was increased from 1 to 4, the conversion decreased while propene selectivity increased continuously and the best propene yields were obtained for a propane-to-oxygen molar ratio of 1.

Graphical abstract.Figure optionsDownload full-size imageDownload high-quality image (138 K)Download as PowerPoint slideHighlights► Cobalt-containing layered double hydroxides as mixed oxide catalyst precursors. ► Catalysts for propane oxidative dehydrogenation. ► Activity increased with the cobalt content and the reducibility of the catalysts. ► Higher propene selectivity was obtained at lower cobalt content. ► The well-dispersed Co species played a key role in propane oxidative dehydrogenation.

Keywords
Co-containing oxides; Layered double hydroxides; Propane; Oxidative dehydrogenation
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Oxidative dehydrogenation of propane over cobalt-containing mixed oxides obtained from LDH precursors
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 417–418, 29 February 2012, Pages 153–162
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