Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites

Handle URI:
http://hdl.handle.net/10754/600098
Title:
Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites
Authors:
Tope, Balkrishna B.; Balasamy, Rabindran J.; Khurshid, Alam; Atanda, Luqman A.; Yahiro, Hidenori; Shishido, Tetsuya; Takehira, Katsuomi; Al-Khattaf, Sulaiman S.
Abstract:
Catalytic mechanism of ethylbenzene dehydrogenation over Fe-Co/Mg(Al)O derived from hydrotalcites has been studied based on the XAFS and XPS catalyst characterization and the FTIR measurements of adsorbed species. Fe-Co/Mg(Al)O showed synergy, whereas Fe-Ni/Mg(Al)O showed no synergy, in the dehydrogenation of ethylbenzene. Ni species were stably incorporated as Ni2+ in the regular sites in periclase and spinel structure in the Fe-Ni/Mg(Al)O. Contrarily, Co species exists as a mixture of Co3+/Co2+ in the Fe-Co/Mg(Al)O and was partially isolated from the regular sites in the structures with increasing the Co content. Co addition enhanced Lewis acidity of Fe3+ active sites by forming Fe3+-O-Co 3+/2+(1/1) bond, resulting in an increase in the activity. FTIR of ethylbenzene adsorbed on the Fe-Co/Mg(Al)O clearly showed formations of C-O bond and π-adsorbed aromatic ring. This suggests that ethylbenzene was strongly adsorbed on the Fe3+ acid sites via π-bonding and the dehydrogenation was initiated by α-H+ abstraction from ethyl group on Mg2+-O2- basic sites, followed by C-O-Mg bond formation. The α-H+ abstraction by O2-(-Mg 2+) was likely followed by β-H abstraction, leading to the formations of styrene and H2. Such catalytic mechanism by the Fe 3+ acid-O2-(-Mg2+) base couple and the Fe 3+/Fe2+ reduction-oxidation cycle was further assisted by Co3+/Co2+, leading to a good catalytic activity for the dehydrogenation of ethylbenzene. © 2011 Elsevier B.V. All rights reserved.
Citation:
Tope BB, Balasamy RJ, Khurshid A, Atanda LA, Yahiro H, et al. (2011) Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites. Applied Catalysis A: General 407: 118–126. Available: http://dx.doi.org/10.1016/j.apcata.2011.08.032.
Publisher:
Elsevier BV
Journal:
Applied Catalysis A: General
Issue Date:
Nov-2011
DOI:
10.1016/j.apcata.2011.08.032
Type:
Article
ISSN:
0926-860X
Sponsors:
This publication was based on work supported by Award No. K-C1-019-12 made by King Abdullah University of Science and Technology (KAUST). The support of King Fahd University of Petroleum and Minerals (KFUPM) is also highly appreciated. The XAFS measurements at the SPring-8 were carried out by the approval (proposal No. 2010B1184) of Japan Synchrotron Radiation Research Institute (JASRI). The authors also acknowledge Japan Cooperation Center, Petroleum (JCCP) for giving the opportunity of this collaborative research.
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DC FieldValue Language
dc.contributor.authorTope, Balkrishna B.en
dc.contributor.authorBalasamy, Rabindran J.en
dc.contributor.authorKhurshid, Alamen
dc.contributor.authorAtanda, Luqman A.en
dc.contributor.authorYahiro, Hidenorien
dc.contributor.authorShishido, Tetsuyaen
dc.contributor.authorTakehira, Katsuomien
dc.contributor.authorAl-Khattaf, Sulaiman S.en
dc.date.accessioned2016-02-28T07:58:47Zen
dc.date.available2016-02-28T07:58:47Zen
dc.date.issued2011-11en
dc.identifier.citationTope BB, Balasamy RJ, Khurshid A, Atanda LA, Yahiro H, et al. (2011) Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites. Applied Catalysis A: General 407: 118–126. Available: http://dx.doi.org/10.1016/j.apcata.2011.08.032.en
dc.identifier.issn0926-860Xen
dc.identifier.doi10.1016/j.apcata.2011.08.032en
dc.identifier.urihttp://hdl.handle.net/10754/600098en
dc.description.abstractCatalytic mechanism of ethylbenzene dehydrogenation over Fe-Co/Mg(Al)O derived from hydrotalcites has been studied based on the XAFS and XPS catalyst characterization and the FTIR measurements of adsorbed species. Fe-Co/Mg(Al)O showed synergy, whereas Fe-Ni/Mg(Al)O showed no synergy, in the dehydrogenation of ethylbenzene. Ni species were stably incorporated as Ni2+ in the regular sites in periclase and spinel structure in the Fe-Ni/Mg(Al)O. Contrarily, Co species exists as a mixture of Co3+/Co2+ in the Fe-Co/Mg(Al)O and was partially isolated from the regular sites in the structures with increasing the Co content. Co addition enhanced Lewis acidity of Fe3+ active sites by forming Fe3+-O-Co 3+/2+(1/1) bond, resulting in an increase in the activity. FTIR of ethylbenzene adsorbed on the Fe-Co/Mg(Al)O clearly showed formations of C-O bond and π-adsorbed aromatic ring. This suggests that ethylbenzene was strongly adsorbed on the Fe3+ acid sites via π-bonding and the dehydrogenation was initiated by α-H+ abstraction from ethyl group on Mg2+-O2- basic sites, followed by C-O-Mg bond formation. The α-H+ abstraction by O2-(-Mg 2+) was likely followed by β-H abstraction, leading to the formations of styrene and H2. Such catalytic mechanism by the Fe 3+ acid-O2-(-Mg2+) base couple and the Fe 3+/Fe2+ reduction-oxidation cycle was further assisted by Co3+/Co2+, leading to a good catalytic activity for the dehydrogenation of ethylbenzene. © 2011 Elsevier B.V. All rights reserved.en
dc.description.sponsorshipThis publication was based on work supported by Award No. K-C1-019-12 made by King Abdullah University of Science and Technology (KAUST). The support of King Fahd University of Petroleum and Minerals (KFUPM) is also highly appreciated. The XAFS measurements at the SPring-8 were carried out by the approval (proposal No. 2010B1184) of Japan Synchrotron Radiation Research Institute (JASRI). The authors also acknowledge Japan Cooperation Center, Petroleum (JCCP) for giving the opportunity of this collaborative research.en
dc.publisherElsevier BVen
dc.subjectC-O bond formationen
dc.subjectEthylbenzene dehydrogenationen
dc.subjectEXAFSen
dc.subjectFe3+-O-Co 3+/2+(1/1) active speciesen
dc.subjectFTIRen
dc.subjectHydrotalciteen
dc.subjectStyreneen
dc.titleCatalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcitesen
dc.typeArticleen
dc.identifier.journalApplied Catalysis A: Generalen
dc.contributor.institutionDepartment of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japanen
dc.contributor.institutionDepartment of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japanen
dc.contributor.institutionDepartment of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japanen
kaust.authorTope, Balkrishna B.en
kaust.authorBalasamy, Rabindran J.en
kaust.authorKhurshid, Alamen
kaust.authorAtanda, Luqman A.en
kaust.authorAl-Khattaf, Sulaiman S.en
kaust.grant.fundedcenterKAUST Center In Development at KFUPMen
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