TY - JOUR
T1 - Influence of surface vacancy defects on the carburisation of Fe 110 surface by carbon monoxide
AU - Chakrabarty, Aurab
AU - Bouhali, Othmane
AU - Mousseau, Normand
AU - Becquart, Charlotte S.
AU - El-Mellouhi, Fedwa
N1 - Publisher Copyright:
© 2016 Author(s).
PY - 2016/7/28
Y1 - 2016/7/28
N2 - Adsorption and dissociation of gaseous carbon monoxide (CO) on metal surfaces is one of the most frequently occurring processes of carburisation, known as primary initiator of metal dusting corrosion. Among the various factors that can significantly influence the carburisation process are the intrinsic surface defects such as single surface vacancies occurring at high concentrations due to their low formation energy. Intuitively, adsorption and dissociation barriers of CO are expected to be lowered in the vicinity of a surface vacancy, due to the strong attractive interaction between the vacancy and the C atom. Here the adsorption energies and dissociation pathways of CO on clean and defective Fe 110 surface are explored by means of density functional theory. Interestingly, we find that the O adatom, resulting from the CO dissociation, is unstable in the electron-deficit neighbourhood of the vacancy due to its large electron affinity, and raises the barrier of the carburisation pathway. Still, a full comparative study between the clean surface and the vacancy-defected surface reveals that the complete process of carburisation, starting from adsorption to subsurface diffusion of C, is more favourable in the vicinity of a vacancy defect.
AB - Adsorption and dissociation of gaseous carbon monoxide (CO) on metal surfaces is one of the most frequently occurring processes of carburisation, known as primary initiator of metal dusting corrosion. Among the various factors that can significantly influence the carburisation process are the intrinsic surface defects such as single surface vacancies occurring at high concentrations due to their low formation energy. Intuitively, adsorption and dissociation barriers of CO are expected to be lowered in the vicinity of a surface vacancy, due to the strong attractive interaction between the vacancy and the C atom. Here the adsorption energies and dissociation pathways of CO on clean and defective Fe 110 surface are explored by means of density functional theory. Interestingly, we find that the O adatom, resulting from the CO dissociation, is unstable in the electron-deficit neighbourhood of the vacancy due to its large electron affinity, and raises the barrier of the carburisation pathway. Still, a full comparative study between the clean surface and the vacancy-defected surface reveals that the complete process of carburisation, starting from adsorption to subsurface diffusion of C, is more favourable in the vicinity of a vacancy defect.
UR - http://www.scopus.com/inward/record.url?scp=85020225267&partnerID=8YFLogxK
U2 - 10.1063/1.4958966
DO - 10.1063/1.4958966
M3 - Article
AN - SCOPUS:85020225267
SN - 0021-9606
VL - 145
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 4
M1 - 044710
ER -