Adsorption of a carbon atom on the Ni38 magic cluster and three low-index nickel surfaces:: A comparative first-principles study -: art. no. 205413

Significant current interest exists in the catalytic growth of carbon (C) nanotubes on clusters of transition metal catalysts. Here we focus on the elemental energetics for the atomistic rate processes involved in the initial stages of the growth by studying a C atom on a nickel (Ni) magic cluster (Ni-38), which preserves fcc geometry, and three low-index extended Ni surfaces. Our methods are based on density-functional theory. The binding energies of a C atom on the extended Ni surfaces and the corresponding facets on the Ni cluster have been obtained and compared. In spite of the large difference in the curvature, the preference order of the adsorption sites for both the cluster and the extended surfaces is unchanged, which shows that among the stable (100), (111) hcp, and (111) fcc sites the (100) has the lowest energy. The diffusion barriers for a C atom on the three low-index surfaces, namely (100), (110), and (111), have also been obtained, with the highest mobility on the Ni(111) surface.