Structural and Electronic Properties of Metal/Oxide Nanostructures from first-principles: Ru13 supported on (TiO2)84 as a case study

All electron density functional theory based calculations are carried out to investigate the properties of metal/oxide nanostructures taking the case of a Ru13 cluster supported on an octahedral anatase (TiO2)84 nanoparticle, as a representative systems. The interaction between both system is exothermic showing binding energies below -4 eV. In spite of the large interaction, the structure of the (TiO2)84 nanoparticle remains unaltered. However, the metal-support interaction promotes the deformation of the Ru13 cluster atomic structure. This deformation is more accentuated when the Ru13 nanocluster is situated in the facet region of the (TiO2)84 nanoparticle than when the interaction involves the edge regions. The formation of the Ru13/(TiO2)84 heterostructure leads to a decrease of the energy gap inherent to the bare (TiO2)84 nanoparticle, becoming almost negligible. This is due to the contribution of the partially filled Ru 4d orbitals with Kohn-Sham energies spanning in the energy range of those of the O 2p occupied and Ti 3d empty manifolds. This feature systematically observed no matter the interaction involves the oxide nanoparticle facet or edge regions. This study constitutes a first step in designing a strategy to investigate metal-semiconductor nanostructures using realistic models that go beyond the use of extended surfaces