Density functional study of the interaction of CO with nickel clusters

The adsorption of CO on the Ni-n cluster surfaces has been systematically investigated by density functional theory. The result indicates that the lowest energy structures of Ni-n CO are generated with CO being adsorbed on Ni-n clusters, and the lowest energy structures of Ni-n clusters are not changed by adsorbing CO molecule, The chemisorption of CO on Ni-n cluster surfaces belongs to non-dissociative adsorption. The increased theoretical CO bond length of 0.1180 - 0.1214 nm (compared with 0.1138 nm) demonstrates the activation of the CO bond. Natural bond orbital analysis shows that the interaction between Ni atoms and CO molecule is primarily contributed by the hybridized molecular orbital within CO and 3d, 4s, 4p orbital of Ni atoms