Ultrathin surface oxides on transition metals: growth and catalytic properties
Florian MITTENDORFER
Institute of Applied Physics and Center for Computational Materials Science TU Vienna, Vienna, Austria
17:00 - 18:00 Tuesday 28 June 2011 KFU The oxidation of several late transition metals leads to the formation of ultrathin surface oxides.
These structures often display unique electronic and structural properties, which allow to fundamentally change the functionality and the chemical properties of the surface. Density functional theory calculations, as implemented in the Vienna Ab-initio Simulations Package (VASP), allow to study these novel properties on a quantum-mechanical level. In this presentation, several examples of the oxidic nanostructures will be discussed:
In the first example, I will elucidate the role of surface oxides on the oxidation of a flat Rh(111) surface. The two-dimensional surface oxide on Rh(111) leads to a passivation of the surface. In addition, we have identified low-dimensional precursors to the oxide layers, which can suppress the formation of the oxide film [1].
In a second example, I will illustrate that the structurally closely related NiO2 stripes on a metallic Rh support drastically change the chemical properties of the surface. This allows to design novel catalysts with localized reaction centers, as demonstrated for the oxidation of CO at these nanostructures[2].
[1] J. Klikovits, et al., Phys. Rev. Lett. 101 (2008) 266104.
[2] S. Surnev, et al., ChemPhysChem 11 (2010) 2506.
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