The binding of a single metal atom (Pt, Pd, Au, and Sn) nearby a single vacancy on the graphene was investigated using the first-principles density-functional theory. On the pristine graphene (pri-graphene), the Pt, Pd, and Sn prefer to be adsorbed at the bridge site, while Au prefers the top site. On the graphene with a single-vacancy graphene, all the metal atoms prefer to be trapped at the vacancy site and appeared as dopants. However, the trapping abilities of the single vacancy graphene were varied for different metal atoms, i.e., the Pt and Pd have the larger trapping zones than do the others. The diffusion barrier of a metal atom on the single vacancy graphene was much higher than that on the pri-graphene, and the Pt atom has the largest diffusion barrier from the single vacancy site to the neighboring bridge sites. On the single vacancy graphene, more electrons were transferred from the adatoms (or dopants) to the carbon atoms at the defect site, which induces changes in the electronic structures and magnetic properties of the systems. This work provides valuable information on the selectivity of lattice vacancy in trapping metal atoms, which would be vital for the atomic-scale design of new metal-carbon nanostructures and graphene-based catalysts.

Trapping of Metal Atoms in the Defects on Graphene. Tang, Y., Yang, Z., Dai, X.: Journal of Chemical Physics, 2011, 135[22], 224704