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Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst
Author(s) -
Chen Wei,
Zijlstra Bart,
Filot Ivo A. W.,
Pestman Robert,
Hensen Emiel J. M.
Publication year - 2018
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201701203
Subject(s) - dissociation (chemistry) , fischer–tropsch process , catalysis , chemistry , carbon monoxide , cobalt , photochemistry , scrambling , inorganic chemistry , selectivity , organic chemistry , linguistics , philosophy
The way in which the triple bond in CO dissociates, a key reaction step in the Fischer–Tropsch (FT) reaction, is a subject of intense debate. Direct CO dissociation on a Co catalyst was probed by 12 C 16 O/ 13 C 18 O scrambling in the absence and presence of H 2 . The initial scrambling rate without H 2 was significantly higher than the rate of CO consumption under CO hydrogenation conditions, which indicated that the surface contained sites sufficiently reactive to dissociate CO without the assistance of H atoms. Only a small fraction of the surface was involved in CO scrambling. The minor influence of CO scrambling and CO residence time on the partial pressure of H 2 showed that CO dissociation was not affected by the presence of H 2 . The positive H 2 reaction order was correlated to the fact that the hydrogenation of adsorbed C and O atoms was slower than CO dissociation. Temperature‐programmed in situ IR spectroscopy underpinned the conclusion that CO dissociation does not require H atoms.