Oxidation of Pdn (n=1-5) clusters on single vacancy graphene: A first-principles study

We performed extensive density-functional calculations to investigate the stability and electronic structure of Pd-n (n = 1-5) clusters supported on single vacancy graphene surface, and adsorption of an oxygen molecule on such clusters were studied in detail. Interaction of the oxygen molecule with bare Pd cluster was also calculated for comparison. Our results show that point defect acts as a strong binding trap for Pd clusters and is favorable for the dispersion of the Pd nanoparticles. Electronic properties analysis shows that there are electrons flowing from Pd clusters to graphene. In addition, the change of the DOS for Pd cluster are mostly attributed to the hybridization of Pd atoms and the directly adjacented three dangling C atoms. Comparative analysis of oxygen molecule adsorption on bare Pd clusters and graphene-supported Pd clusters, the existence of graphene support promotes more electrons to transfer to oxygen molecule and further makes the O-O bond elongation, which indicates graphene may be used as an effective support material. Besides, an energy decomposition scheme is also employed to give insight into the impact of graphene support on the oxygen molecule adsorption behavior. (C) 2013 Elsevier B.V. All rights reserved.