Ethylbenzene dehydrogenation over FeOx/(Mg,Zn)(Al)O catalysts derived from hydrotalcites: Role of MgO as basic sites

Rabindran J. Balasamy, Balkrishna B. Tope, Alam Khurshid, Ali A S Al-Ali, Luqman A. Atanda, Kunimasa Sagata, Makiko Asamoto, Hidenori Yahiro, Kiyoshi Nomura, Tsuneji Sano, Katsuomi Takehira, Sulaiman S. Al-Khattaf

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

A series of Mg3-xZnxFe0.5Al0.5 mixed oxide catalysts derived from hydrotalcites were tested in the ethylbenzene dehydrogenation to styrene in He atmosphere at 550 °C. The catalysts were prepared by coprecipitation from the nitrates of metal components followed by calcination to mixed oxides at 550 °C. A part of Mg2+ in Mg 3Fe0.5Al0.5 mixed oxide was replaced with Zn2+ to test the effect of MgO as the support. The mixed oxides were composed of periclase and spinel-type compounds with a high surface area of 100-180m2gcat-1. Mössbauer and XPS measurements indicated the presence of Fe3+ on the catalysts and H2-TPR measurement suggested that the dehydrogenation reaction is catalyzed by the reduction-oxidation between Fe3+/Fe2+. The activity of Mg3-xZnxFe0.5Al0.5 mixed oxide decreased with increasing x, indicating an important role of MgO on the activity. Both CO2-TPD measurements as well as IR measurements of adsorbed CO2 clearly indicated the presence of basic sites of Mg 2+O2- on the catalysts. It seems that the combination of Mg2+O2- and Fe3+ was essential for the catalytic activity. It is concluded that the surface base sites generated on O2- bound Mg2+ near Fe3+ sites are responsible for H+-abstraction; the dehydrogenation of ethylbenzene was initiated by the H+ abstraction on Mg2+O2- basic sites, and accelerated by the reduction-oxidation of Fe3+/Fe2+ active species. © 2011 Elsevier B.V.
Original languageEnglish (US)
Pages (from-to)113-122
Number of pages10
JournalApplied Catalysis A: General
Volume398
Issue number1-2
DOIs
StatePublished - May 2011
Externally publishedYes

Fingerprint Dive into the research topics of 'Ethylbenzene dehydrogenation over FeOx/(Mg,Zn)(Al)O catalysts derived from hydrotalcites: Role of MgO as basic sites'. Together they form a unique fingerprint.

Cite this