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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

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.

Zugehörige Institution(en) am KIT Institut für Katalyseforschung und -Technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1088/1742-6596/712/1/012050
ISSN: 1742-6588, 1742-6596
URN: urn:nbn:de:swb:90-654531
KITopen ID: 1000065453
HGF-Programm 37.03.01; LK 01
Erschienen in Journal of physics / Conference Series
Band 712
Seiten 012050
Lizenz CC BY 3.0 DE: Creative Commons Namensnennung 3.0 Deutschland
Bemerkung zur Veröffentlichung 16th International Conference on X-ray Absorption Fine Structure (XAFS16), Karlsruhe, August 23-28, 2015
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