Adsorption and dissociation of CO on metal clusters

Adsorption and dissociation of carbon monoxide on metal clusters M-13 (M = Ag, Co, Cu, Fe, Ni and Ru), has been studied. Structure stabilities of metal clusters, adsorption sites, adsorption energies and the activation energies for the dissociation of CO were determined using density functional theory. Cohesive and binding energies of metal atoms in M-13 clusters of studied metals were calculated, showing the different strength interaction of metal atoms in each particle. Three active adsorption sites on the M-13 particles studied have been identified, showing that CO adsorption with covalent nature can occur on different sites depending of the metal cluster. Charge density difference in the M-13-CO interaction on all the adsorption sites of all metal clusters showed a strong accumulation of charge density in the M-C bonding. Of the group of metal cluster modeled, Ru-13, Cu-13 and Co-13 present higher adsorption energies. On the other hand, Fe-13, Co-13 and Ru-13 present lower activation energies. In all cases, endothermic behavior of CO dissociation was observed. The initial stages of CO interaction with several metal clusters, in comparison with metal surfaces, is presented.