Chemisorption of CO on the Fe2�1�1 surface is studied within first-principles
density functional theory (DFT) and single-crystal adsorption calorimetry
(SCAC). The most stable molecular adsorption state corresponds to
CO bound in a three-fold site involving one metal atom from the top
layer and two metal atoms in the second layer. In this configuration,
CO is tilted and elongated with a considerably red-shifted stretching
frequency (calculated to be 1634�cm-1 as opposed to 2143�cm-1 for
gas-phase CO). This state is very similar to that of CO on Fe1�0�0
and Fe1�1�1, which is believed to be a precursor state to dissociation
at relatively modest temperatures. However, dissociation of CO is
found by DFT to be particularly facile on Fe2�1�1, with a dissociation
barrier noticeably lower than that for CO on Fe1�0�0 or Fe1�1�1.
The 300�K coverage-dependent calorimetric data is consistent with
either molecular or dissociative adsorption, with an initial adsorption
heat of 160�kJ/mol. At higher coverages, the heat of adsorption and
sticking probability data exhibit a forced oscillatory behaviour,
which can be explained by assuming CO dissociation and subsequent
diffusion of atomic carbon and/or oxygen into the substrate. It is
argued that conditions for CO dissociation on Fe2�1�1 are nearly
optimal for Fischer-Tropsch catalysis.
%0 Journal Article
%1 Borthwick2008
%A Borthwick, David
%A Fiorin, Vittorio
%A Jenkins, Stephen J.
%A King, David A.
%D 2008
%J Surface Science
%K CO, Density calculations, functional iron microcalorimetry, science, surface
%N 13
%P 2325 - 2332
%R DOI: 10.1016/j.susc.2008.05.014
%T Facile dissociation of CO on Fe2�1�1: Evidence from microcalorimetry
and first-principles theory
%U http://www.sciencedirect.com/science/article/B6TVX-4SK07P0-2/2/83e5565cf9ed038727428d22ffd49eb2
%V 602
%X Chemisorption of CO on the Fe2�1�1 surface is studied within first-principles
density functional theory (DFT) and single-crystal adsorption calorimetry
(SCAC). The most stable molecular adsorption state corresponds to
CO bound in a three-fold site involving one metal atom from the top
layer and two metal atoms in the second layer. In this configuration,
CO is tilted and elongated with a considerably red-shifted stretching
frequency (calculated to be 1634�cm-1 as opposed to 2143�cm-1 for
gas-phase CO). This state is very similar to that of CO on Fe1�0�0
and Fe1�1�1, which is believed to be a precursor state to dissociation
at relatively modest temperatures. However, dissociation of CO is
found by DFT to be particularly facile on Fe2�1�1, with a dissociation
barrier noticeably lower than that for CO on Fe1�0�0 or Fe1�1�1.
The 300�K coverage-dependent calorimetric data is consistent with
either molecular or dissociative adsorption, with an initial adsorption
heat of 160�kJ/mol. At higher coverages, the heat of adsorption and
sticking probability data exhibit a forced oscillatory behaviour,
which can be explained by assuming CO dissociation and subsequent
diffusion of atomic carbon and/or oxygen into the substrate. It is
argued that conditions for CO dissociation on Fe2�1�1 are nearly
optimal for Fischer-Tropsch catalysis.
@article{Borthwick2008,
abstract = {Chemisorption of CO on the Fe{2�1�1} surface is studied within first-principles
density functional theory (DFT) and single-crystal adsorption calorimetry
(SCAC). The most stable molecular adsorption state corresponds to
CO bound in a three-fold site involving one metal atom from the top
layer and two metal atoms in the second layer. In this configuration,
CO is tilted and elongated with a considerably red-shifted stretching
frequency (calculated to be 1634�cm-1 as opposed to 2143�cm-1 for
gas-phase CO). This state is very similar to that of CO on Fe{1�0�0}
and Fe{1�1�1}, which is believed to be a precursor state to dissociation
at relatively modest temperatures. However, dissociation of CO is
found by DFT to be particularly facile on Fe{2�1�1}, with a dissociation
barrier noticeably lower than that for CO on Fe{1�0�0} or Fe{1�1�1}.
The 300�K coverage-dependent calorimetric data is consistent with
either molecular or dissociative adsorption, with an initial adsorption
heat of 160�kJ/mol. At higher coverages, the heat of adsorption and
sticking probability data exhibit a forced oscillatory behaviour,
which can be explained by assuming CO dissociation and subsequent
diffusion of atomic carbon and/or oxygen into the substrate. It is
argued that conditions for CO dissociation on Fe{2�1�1} are nearly
optimal for Fischer-Tropsch catalysis.},
added-at = {2009-10-30T10:04:05.000+0100},
author = {Borthwick, David and Fiorin, Vittorio and Jenkins, Stephen J. and King, David A.},
biburl = {https://www.bibsonomy.org/bibtex/25ee146dc31e350d9a10d0a195baadcff/jfischer},
doi = {DOI: 10.1016/j.susc.2008.05.014},
interhash = {421a19b357efe2b2e76cba2e70c780b7},
intrahash = {5ee146dc31e350d9a10d0a195baadcff},
issn = {0039-6028},
journal = {Surface Science},
keywords = {CO, Density calculations, functional iron microcalorimetry, science, surface},
number = 13,
pages = {2325 - 2332},
timestamp = {2009-10-30T10:04:07.000+0100},
title = {Facile dissociation of CO on Fe{2�1�1}: Evidence from microcalorimetry
and first-principles theory},
url = {http://www.sciencedirect.com/science/article/B6TVX-4SK07P0-2/2/83e5565cf9ed038727428d22ffd49eb2},
volume = 602,
year = 2008
}