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ID 117154
Title Alternative
Carbon Deposition Assisting the Enhancement of Catalytic Activity with Time-on-Stream in the Dehydrogenation of Isobutane on NiO/Al2O3
Author
Yoshida, Tashu Tokushima University
Kato, Yuki Mitsubishi Chemical Corporation
Ninomiya, Wataru Mitsubishi Chemical Corporation
Keywords
Dehydrogenation
Isobutane
Nickel Oxide
Catalyst Deactivation
Carbon Deposition
Content Type
Journal Article
Description
In the transformation reaction of alkanes to alkenes via catalytic dehydrogenation, it is generally accepted that the so-called catalytic deactivation behavior will occur. This phenomenon causes a drastic reduction in activity with time-on-stream. It is understood that carbon deposition generated during the reaction then covers the surface of the catalyst, and this leads to a drastic decrease in activity. However, contrary to this common wisdom, our laboratory reported that the dehydrogenation of isobutane to isobutene on NiO/γ-Al2O3 within a specific range of NiO loading in the presence of CO2 actually improved the yield of isobutene with time-on-stream. Since few such cases have been reported, in this study, isobutane was dehydrogenated in the presence of CO2 using NiO/α-Al2O3 as the catalyst with 20% NiO loading and improvement was again observed. In order to investigate the cause of the improvement, both NiO/γ-Al2O3 and NiO/α-Al2O3 with 20% NiO loading were examined in detail following the reaction. According to TEM analysis, both catalysts were covered with a large amount of carbon deposition after the reaction, but there was a difference in the types. The carbon deposition on NiO/γ-Al2O3 had a fibrous nature while that on NiO/α-Al2O3 appeared to be a type of nanowire. Raman spectroscopy revealed that the carbonaceous crystal growth properties of two forms differed depending on the support. In particular, a catalytically active species of metallic nickel was formed in a high degree of dispersion in and on the above two forms of carbon deposition during the reaction, and this resulted in high activity even if the catalyst was covered with a carbon deposition.
Journal Title
Journal of Chemical Engineering of Japan
ISSN
00219592
NCID
AA00709658
Publisher
The Society of Chemical Engineers, Japan
Volume
55
Issue
7
Start Page
248
End Page
254
Published Date
2022-07-20
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Author
departments
Science and Technology
Technical Support Department