Interaction of CO, O, and CO₂ with Cu cluster supported on Cu(1 1 1): a density functional theory study

We performed density functional theory (DFT) based calculations to investigate the interaction of CO₂ and its dissociated species (CO and O) on Cu₃ cluster supported on Cu(1 1 1) (Cu₃/Cu(1 1 1)) surfaces. Similar investigations were conducted on Cu(1 1 1) for purpose of comparison. In general, adsorption of CO and O are stronger on the cluster region than on the terrace region of Cu₃/Cu and on the flat Cu surface. CO₂, on the other hand, is weakly adsorbed on the surfaces. With reference to CO₂ dissociation on Cu(1 1 1), we found that the cluster lowers the activation barrier and provides a more stable adsorption of the dissociated species. The presence of co-adsorbed CO in the cluster, however, will increase the activation energy. The variation in the activation barrier with the amount of CO is influenced by the stability of the O atom from the dissociated CO₂. We further found that the adsorption energy of O atom is a possible descriptor for CO₂ dissociation on the cluster region. The Cu cluster supported on Cu surface could be a promising catalyst for CO₂ related reactions based on the lower activation energy for CO₂ dissociation on the system than on Cu(1 1 1).