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Tunable activity of [Ga]HZSM-5 with H2 treatment: Ethane dehydrogenation

Paper ID Volume ID Publish Year Pages File Format Full-Text
49742 46764 2014 6 PDF Available
Title
Tunable activity of [Ga]HZSM-5 with H2 treatment: Ethane dehydrogenation
Abstract

•Reduced Ga species is more active than the oxide species for ethane dehydrogenation.•GaH2+ is the most active species and only available under stream of H2.•Treating [Ga]HZSM-5 with H2 and/or H2O results in re-dispersion of Ga species.

Ethane dehydrogenation over [Ga]HZSM-5 catalyst were studied to probe activity of various gallium species (Ga2O3, GaO+, Ga+, and GaH2+) in a pulsed reactor. H2-TPR was used for characterizing the reducible Ga species. It was found that the activity of [Ga]HZSM-5 can be regulated by the H2 treatment. Among the various Ga species, the H2-incorporated species (i.e. GaH2+) displays the highest dehydrogenation activity (~ 55% conversion) under the H2 stream. However, this so-called GaH2+ can readily decompose in the absence of H2, presumably to Ga+ that give a lower ethane conversion (~ 30%). While the Ga oxide species, which may well be retained as isolated Ga2O3 and exchangeable GaO+, provide the lowest dehydrogenation activity (~ 25% conversion). The lower activity is observed with an increase in the Si/Al ratio of the host zeolite, suggesting that the active site is associated with the negative framework charge, presumably as a charge balancing cation (i.e. GaH2+, Ga+, GaO+). In addition, treatment with hydrogen and steam can readily disperse occluded Ga2O3 into exchangeable Ga+ and GaO+, respectively.

Keywords
[Ga]HZSM-5; Ethane dehydrogenation; Ga species; Pulsed reactor
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Tunable activity of [Ga]HZSM-5 with H2 treatment: Ethane dehydrogenation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Communications - Volume 45, 5 February 2014, Pages 63–68
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
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Price was $35.95
You save - $31
Price after discount Only $4.95
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Any Questions? feel free to contact us