Understanding heterogeneous catalysis on an atomic scale: a combined surface science and reactivity investigation for the dehydrogenation of ethylbenzene over iron oxide catalysts |
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Authors: | Kuhrs C Arita Y Weiss W Ranke W Schlögl R |
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Affiliation: | (1) Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany |
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Abstract: | In order to study the dehydrogenation of ethylbenzene to styrene, epitaxial iron oxide model catalyst films with Fe3O4(111), -Fe2O3(0001) and KFe
x
O
y
(111) stoichiometry were prepared in single crystal quality on Pt(111). They were investigated using surface science techniques before and after atmospheric pressure reaction experiments in a newly designed single crystal flow reactor. As expected from low-pressure measurements, Fe3O4(111) is catalytically inactive. The catalytic activity of -Fe2O3(0001) starts after an activation period of about 45 min. After that, the surface is essentially clean but shows a high concentration of defects. On the potassium-promoted films, however, the activation period is much longer, the activity then is higher and the surface gets covered completely with carbon and oxygen during reaction. This indicates a different reaction pathway on the promoted films with a carbon–oxygen species as catalytically active species. |
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Keywords: | metal oxides atomic scale surface chemistry TDS single crystal flow reactor high pressure pressure gap defects active carbon |
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