Density functional study of Pd nanoparticles with subsurface impurities of light element atoms

摘要: Atomic H, C, N and O at the surface in subsurface region of Pd nanoparticles were studied theoretically using an all-electron scalar relativistic density functional approach. We modelled nanosize metal clusters by three-dimensional crystallites Pd79 Pd116 chosen as octahedral fragments bulk Pd; these expose (111) (001) facets. Adsorbed atoms located three-fold hollow sites centre Migration from cluster to (oss) site below was considered. C oss position found be almost isoenergetic; migration H is somewhat endothermic (by 0.5 eV). For O, a lager endothermicity calculated. Both species exhibit moderate activation barriers for diffusion site. tetrahedral (tss) also studied. both species, this location energetically disfavoured, although effect atom tss ∼0.5 eV smaller than Subsurface impurities calculated reduce adsorption energy CO molecules clusters.