CO Binding on Noble Metal Clusters

The previous sections discussed using CO as a reporter on the electron rich-ness/deficiency of It4 clusters as well as the effect of electron richness itself on the binding energy of CO. This section investigates CO binding on gold clusters and provides a relevant catalytic application of these studies CO oxidation. 

As mentioned previously with reference to the Sabatier principle, there is a delicate balance that must be achieved between a reactant binding too strongly or too weakly to a catalyst. Norskov et al. [28] performed a DFT study that correlated the activation energies of N2, CO, NO, and O2 dissociation with the heat of adsorption on a variety of different metal surfaces. These relations are structure-sensitive (closed-packed surfaces versus steps) due to the dependence of the transition-state barrier on the openness of the metal surface. The relationship shows that the activation energy decreases as the binding energy of the adsorbate increases [28]. Another example of structure-sensitive CO binding is from Iwasawa et al. [29], who showed that the adsorption of CO on platinum surfaces occurs associatively on terraces while dissociative chemisorption dominates on step and kink sites. 

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