Density functional study of gold atoms and clusters on a graphite (0001) surface with defects

Akola, J.; Häkkinen, H.

doi:10.1103/PhysRevB.74.165404

Journal Article

PreJuSER-57125

Density functional study of gold atoms and clusters on a graphite (0001) surface with defects

Akola, J.FZJ* ; Häkkinen, H.

2006
APS College Park, Md.

Physical review / B 74(16), 165404 (2006) [10.1103/PhysRevB.74.165404]

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Please use a persistent id in citations: http://hdl.handle.net/2128/7692 doi:10.1103/PhysRevB.74.165404

Abstract: Adsorption of gold atoms and clusters (N=6) on a graphite (0001) surface with defects has been studied using density functional theory. In addition to perfect graphite (0001), three types of surface defects have been considered: a surface vacancy (hole), a pyridinelike defect comprising three grouped nitrogen atoms, and a substitutional doping by N or B. Results for Au and Au-6 indicate that the surface vacancy can form chemical bonds with Au as the three nearby carbons align their dangling bonds towards the gold particle (binding energy 2.4-2.6 eV). A similar chemically saturated holelike construction with three pyridinic N atoms results in a significant polarization interaction (1.1-1.2 eV), whereas the binding with the perfect graphite surface is weak (similar to 0.3 eV). The corresponding energies for the B/N substituted surface are 0.8-1.2 eV (B) and 0.2-0.6 eV (N), and the N impurity donates charge to Au/Au-6. Several Au-6 isomers have been tested in different orientations on substrate, and the triangular gas-phase geometry (D-3h) standing on its apex is a low-energy configuration (N substitution is an exception). In general, coordination through corner atoms is energetically favorable. For the surface vacancy, the presence of gold particles leads to a significant surface reconstruction, whereas the pyridinelike defect appears rigid. There is no significant charge transfer, and the net charge on Au-6 ranges between -0.2e and 0.1e.

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