Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 81: Oxides and Insulator Surfaces I
O 81.11: Talk
Thursday, March 10, 2016, 13:15–13:30, H4
DFT study of metallic adsorbates on bulk and thin films of Zirconia — •Wernfried Mayr-Schmölzer, Florian Mittendorfer, and Josef Redinger — Inst. of Applied Physics, TU Wien, Vienna, Austria
Zirconia (ZrO2) is a material with many interesting properties, making it useful for various technological applications, such as a solid electrolyte in solid-oxide fuel-cells or as an oxygen gas sensor. Therefore, a detailed understanding of adsorption and interface properties of Zirconia is very useful. We present results of DFT calculations for the adsorption of metal adatoms and clusters on bulk surfaces and on thin Zirconia films grown by oxidation of a Pt3Zr substrate. The calculations were performed using the Vienna Ab-Initio Simulation Package (VASP) employing van-der-Waals density functionals. The bonding and adsorption mechanism was studied for various metal adatoms such as noble Au and Ag as well as reactive Ni and Pd. On bulk surfaces we only find a weak physisorption for noble Au and even weaker for Ag (≈ 0.5eV), while reactive Ni and Pd show significantly higher adsorption energies (> 2.0 eV). On a thin supported ZrO2 film a general increase of the adsorption energies by more than 0.5 eV is predicted, resulting a chemisorbed state for Ag, wheres Au remains more weakly bound. To investigate mobility and cluster formation of these noble adsorbates we report on the surface diffusion barriers for silver and gold where we find values below 0.5 eV. We also report on the interface energy of silver and gold films of varying thickness on the thin oxide film.