CO Adsorption on Defective Graphene-Supported Pt13 Nanoclusters

Platinum (Pt) nanoclusters on graphene have been shown to possess superior catalytic activity and increased selectivity in a variety of electrochemical reactions compared with bulk Pt electrodes. In this work, we use density functional theory calculations to investigate the adsorption of CO on low energy Pt-13 clusters bound at various point defects in graphene. The presence of dangling bonds at defects in the graphene support leads to strong Pt carbon bonding and a commensurate downshift of the cluster d-band center. This downshift of the d-band in turn decreases the binding energy of CO molecules to the cluster. Systematic random sampling of CO adsorption on clusters bound at various defects in graphene reveals that supported dusters, on average, bind CO more weakly than Unsupported clusters. Moreover, the adsorption energies of CO on defective-graphene-supported clusters are found to be comparable with reported adsorption energies at undercoordinated sites, such as step-edges, on low-index Pt surfaces. Our results suggest that tailoring cluster support interactions through defect engineering could provide a route for improving the tolerance of subnanometer Pt dusters to CO poisoning.