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Dynamic transformation of small Ni particles during methanation of CO under fluctuating reaction conditions monitored by X-ray absorption spectroscopy

Mutz, B; Carvalho, H W P; Kleist, W; Grunwaldt, J-D

Abstract:
A 10 wt.-% Ni/Al$_{2}$O$_{3}$ catalyst with Ni particles of about 4 nm was prepared and applied in the methanation of CO$_{2}$ under dynamic reaction conditions. Fast phase transformations between metallic Ni, NiO and NiCO$_{3}$ were observed under changing reaction atmospheres using operando X-ray absorption spectroscopy (XAS). Removing H$_{2}$ from the feed gas and, thus, simulating a H$_{2}$ dropout during the methanation reaction led to oxidation of the active sites. The initial reduced state of the Ni particles could not be recovered under methanation atmosphere (H$_{2}$/CO$_{2}$ = 4); this was only possible with an effective reactivation step applying H$_{2}$ at increased temperatures. Furthermore, the cycling of the gas atmospheres resulted in a steady deactivation of the catalyst. Operando XAS is a powerful tool to monitor these changes and the behavior of the catalyst under working conditions to improve the understanding of the catalytic processes and deactivation phenomena.

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Volltext §
DOI: 10.5445/IR/1000065453
Originalveröffentlichung
DOI: 10.1088/1742-6596/712/1/012050
Scopus
Zitationen: 6
Zugehörige Institution(en) am KIT Institut für Technische Chemie und Polymerchemie (ITCP)
Institut für Katalyseforschung und -Technologie (IKFT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator ISSN: 1742-6588, 1742-6596
urn:nbn:de:swb:90-654531
KITopen-ID: 1000065453
HGF-Programm 37.03.01 (POF III, LK 01)
Erschienen in Journal of physics / Conference Series
Band 712
Seiten 012050
Bemerkung zur Veröffentlichung 16th International Conference on X-ray Absorption Fine Structure (XAFS16), Karlsruhe, August 23-28, 2015
Nachgewiesen in Scopus
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