The structural and electronic properties of Pt-Cu alloy clusters: Embedding atom method combined with density functional theory study

Using an embedding atom method, the low-lying candidate structures of a large Pt-Cu alloy cluster Pt₈₆Cu₂₂ were obtained through screening 10⁵ isomers. The results indicate that the Pt@PtCu core-shell structures with Pt skin and PtCu core are energetically more stable than the others, which is in good agreement with the experimental observation. Furthermore, an impurity Cu atom is preferred to stay at the subsurface instead of the surface region of Pt-Cu alloy clusters, and the doped Cu atoms prefer to disperse in Pt-Cu alloy. The electronic structures of the EAM optimized structures are calculated with density functional theory, and the projected electronic densities of states reveal that Cu doping can obviously enrich the electronic states of surface Pt atoms near the Fermi level, which may provide some clues for understanding the mechanism of enhancement of the catalytic activity for Pt-Cu alloy catalyst.