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Study of the interaction between components in hybrid CuZnAl/HZSM-5 catalysts and its impact in the syngas-to-DME reaction

Paper ID Volume ID Publish Year Pages File Format Full-Text
55612 47059 2012 9 PDF Available
Title
Study of the interaction between components in hybrid CuZnAl/HZSM-5 catalysts and its impact in the syngas-to-DME reaction
Abstract

Hybrid CuZnAl(CZA)/HZSM-5 catalysts were prepared by three mixing methods in order to analyze the possible existence of interactions between components and their impact in the STD process, namely: (a) grinding of powders prior to pelletizing (grinding method), (b) slurrying the two solids in water followed by drying and pelletizing (slurry method), and (c) physical mixture of pre-pelletized components. The materials were characterized by ICP-OES, XRD, N2 physisorption, H2-TPR, 27Al MAS NMR, FTIR-pyridine, and EPR spectroscopy. Detrimental interactions producing a drastic reduction in the amount of available zeolitic Brønsted acid sites were observed for the hybrids prepared by slurry and grinding methods. Such interactions involved, on one hand, the partial blockage of micropores by CZA particles and, on the other hand, an inter-cationic exchange of Cu2+ (and possibly also Zn2+) species. The presence of isolated Cu2+ cations occupying exchange positions in the HZSM-5 zeolite was unambiguously evidenced by EPR spectroscopy. The decrease in Brønsted acidity significantly reduced the activity of the zeolite for dehydrating methanol leading to a much lower efficiency of the corresponding hybrids for DME synthesis at typical STD conditions as compared to the catalyst obtained by simple mixture of pre-pelletized components.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (146 K)Download as PowerPoint slideHighlights► Detrimental CuZnAl–HZSM-5 interactions in hybrid STD catalysts are observed. ► Cu2+ species at exchange zeolitic positions detected by EPR. ► Interactions significantly reduce the catalyst efficiency for DME synthesis.

Keywords
Synthesis gas; Methanol dehydration; Dimethyl ether; Hybrid catalyst; CuZnAl; ZSM-5 zeolite; Detrimental interactions; EPR spectroscopy
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Study of the interaction between components in hybrid CuZnAl/HZSM-5 catalysts and its impact in the syngas-to-DME reaction
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 179, Issue 1, 5 January 2012, Pages 43–51
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