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Structure and reducibility of a Fe/Al₂O₃ catalyst for selective catalytic reduction studied by Fe K-edge XAFS spectroscopy

Boubnov, A. 1; Lichtenberg, H. 1; Mangold, S. 2; Grunwaldt, J.-D.
1 Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
2 Institut für Synchrotronstrahlung (ISS), Karlsruher Institut für Technologie (KIT)


EXAFS and pre-edge information from the Fe K-edge absorption spectra is used in this study to characterise the local environment and geometry of Fe-centres in a 1% Fe/Al2O3 model catalyst. The EXAFS results reveal clusters of 2-3 Fe oxo-moieties dispersed on the Al2O3-support. The Fe3+ centres are coordinated by 6 O-atoms in a strongly distorted octahedral geometry. This is supported by the pre-edge peak, which is far more intense than in α-Fe2O3 absorption data acquired for comparison. For preliminary investigations, catalytic tests for selective catalytic reduction (SCR) of NOx by ammonia and in situ XANES studies of Fe/Al2O3 are compared with previously published data for Fe/zeolite systems. The low SCR activity of Fe/Al2O3 (compared to Fe/zeolite catalysts) in which the Fe3+ species do not change their electronic state under SCR-relevant conditions (reference temperature 250°C in our case) correlates well to the significantly higher temperatures required to reduce these species to Fe2+. The difference in reducibility (and consequently in the SCR-activity) between the two systems probably results from differences in the structure and the electronic interaction of the Fe oxo-moieties and the particular catalyst support.

Verlagsausgabe §
DOI: 10.5445/IR/1000047582
Veröffentlicht am 16.04.2018
DOI: 10.1088/1742-6596/430/1/012054
Zitationen: 10
Zitationen: 9
Cover der Publikation
Zugehörige Institution(en) am KIT ANKA - die Synchrotronstrahlungsquelle am KIT (ANKA)
Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2013
Sprache Englisch
Identifikator ISSN: 1742-6588, 1742-6596
KITopen-ID: 1000047582
HGF-Programm 43.12.01 (POF II, LK 01) Tailored properties of nanomaterials
Erschienen in Journal of physics / Conference Series
Verlag Institute of Physics Publishing Ltd (IOP Publishing Ltd)
Band 430
Heft 1
Seiten 012054/1-4
Nachgewiesen in Dimensions
Web of Science
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