TY - JOUR
T1 - Ethylbenzene dehydrogenation over FeOx/(Mg,Zn)(Al)O catalysts derived from hydrotalcites: Role of MgO as basic sites
AU - Balasamy, Rabindran J.
AU - Tope, Balkrishna B.
AU - Khurshid, Alam
AU - Al-Ali, Ali A S
AU - Atanda, Luqman A.
AU - Sagata, Kunimasa
AU - Asamoto, Makiko
AU - Yahiro, Hidenori
AU - Nomura, Kiyoshi
AU - Sano, Tsuneji
AU - Takehira, Katsuomi
AU - Al-Khattaf, Sulaiman S.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): K-C1-019-12
Acknowledgements: This publication was based on the 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 authors are grateful to Prof. Emeritus H. Hattori of Hokkaido University for helpful discussions. The authors also acknowledged Japan Cooperation Center, Petroleum (JCCP) for giving an opportunity of this collaborative research.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
PY - 2011/5
Y1 - 2011/5
N2 - 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.
AB - 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.
UR - http://hdl.handle.net/10754/600103
UR - https://linkinghub.elsevier.com/retrieve/pii/S0926860X11001554
UR - http://www.scopus.com/inward/record.url?scp=79955470536&partnerID=8YFLogxK
U2 - 10.1016/j.apcata.2011.03.023
DO - 10.1016/j.apcata.2011.03.023
M3 - Article
SN - 0926-860X
VL - 398
SP - 113
EP - 122
JO - Applied Catalysis A: General
JF - Applied Catalysis A: General
IS - 1-2
ER -