Structural changes in FeOx/γ-Al2O3 catalysts during ethylbenzene dehydrogenation. (1st October 2016)

• Record Type: Journal Article
• Authors: Mediero-Munoyerro, M. J.; McGregor, James; McMillan, L.; Al-Yassir, N.; Bingham, P. A.; Forder, S. D.; Gorin, C.; Al-Khattaf, S.; Gladden, L. F.; Midgley, P. A.
• Is Part Of: Catalysis, structure & reactivity. Volume 2:Number 1(/42016)
• Page Start: 25
• Page End: 32
• Publication Date: 2016-10-01
• Subjects: Iron -- Alumina -- Carbonaceous overalyers -- Ethylbenzene -- Styrene; Catalysts -- Periodicals; Catalysis -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; 660.2995
• DOI: 10.1080/2055074X.2016.1234116
• Languages: English
• ISSNs: 2055-074X

Abstract

Abstract: The structural changes that occur in a FeOx /γ-Al2 O3 catalyst during the dehydrogenation of ethylbenzene in a fluidized CREC Riser Simulator have been investigated. Chemical and morphological changes are observed to take place as a result of reaction. Electron microscopy reveals the formation of needle-like alumina structures apparently enclosing iron oxide particles. The formation of such structures at relatively low temperatures is unexpected and has not previously been reported. Additionally, X-ray diffraction and Mössbauer spectroscopy confirmed the reduction of the oxidation state of iron, from Fe2 O3 (haematite) to Fe3 O4 (magnetite). Iron carbides, Fe3 C and ɛ-Fe2 C, were detected by electron microscopy through electron diffraction and lattice fringes analysis. Carbon deposition (coking) on the catalyst surface also occurs. The observed structural changes are likely to be closely correlated with the catalytic properties of the materials, in particular with catalyst deactivation, and thereby provide important avenues for future study of this industrially important reaction. Graphical abstract: Fe2 O3 /Al2 O3 catalyst undergoes chemical and morphological changes during ethylbenzene dehydrogenation forming Al2 O3 needles which appear to contain reduced Fe3 O4 particles. Fe3 C also forms during reaction.