Interaction of carbon monoxide with bimetallic Co-Pt clusters: A density functional theory study

We have studied the interaction of CO with bimetallic ConPtm (n + m <= 5) clusters in the framework of spin-polarized density functional theory by employing the B3LYP xc-functional. Several possible magnetic states and various adsorption sites have been considered. The CO molecule prefers to be adsorbed at the Pt site rather than at the Co site. Atop adsorption pattern is energetically more favored over the hollow and bridge adsorptions. The largest adsorption energy is observed at Co3Pt (2.993 eV). The adsorption strength is correlated with the relative stability of the bare clusters and the electrostatic interactions between the C, O, and metal atoms to which the CO molecule is bound. For higher sizes we predict that high adsorption energies may be expected for relatively less stable bare clusters if the electrostatic interaction between CO and the top metal atom is strong. In addition, the adsorption of CO has different influence on the magnetism of the clusters. (C) 2012 Elsevier B.V. All rights reserved.