Adsorption and activation of CO over flat and stepped Co surfaces: A first principles analysis

Qingfeng Ge, Matthew Neurock

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131 Scopus citations

Abstract

The adsorption and activation of CO over flat Co{0001}, corrugated Co{112̄0}, and stepped Co{101̄2} and Co{112̄4} surfaces have been analyzed using periodic density functional theory calculations. CO strongly chemisorbs on all these surfaces but does not show a strong dependence on the surface structure. The calculated structure of adsorbed CO on Co{0001} at 1/3 monolayer (ML) of coverage was found to be in good agreement with the experiment. The barrier for CO dissociation over Co{0001} was found to decrease with decreasing CO coverage, taking on a value of 232 kJ/mol at 1/4 ML and 218 kJ/mol at 1/9 ML. The presence of the "zigzag" channel on Co{112̄0} enhances the reactivity slightly by reducing the barrier for CO dissociation to 195 kJ/mol. In contrast, the stepped Co{101̄2} and Co{112̄4} surfaces are much more active than the flat and corrugated surfaces. Both stepped surfaces provide direct channels for CO dissociation that do not have barriers with respect to gas-phase CO. In general the activation barriers lower as the reaction energies become more exothermic. Reconstruction of the step edges that occur in the product state, however, prevents a linear correlation between the reaction energy and the activation energy.

Original languageEnglish (US)
Pages (from-to)15368-15380
Number of pages13
JournalJournal of Physical Chemistry B
Volume110
Issue number31
DOIs
StatePublished - Aug 10 2006

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