Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 84: Poster Focus Session: Structure and Chemistry of Metal-Oxide Surfaces

O 84.5: Poster

Wednesday, March 14, 2018, 18:15–20:30, Poster A

Chemical Reactivity of Amorphous Oxide Surfaces — •Hannah Schlott and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg

Theoretical studies on the chemical reactivity of surfaces have been performed almost exclusively for crystalline model surface structures. When it comes to oxides, however, surfaces are typically amorphous and are covered by residuals from the environment, in particular OH groups from contact with water or protective ligand shells in the case of nanoparticles. Using Car-Parrinello Molecular Dynamics (CPMD) we first prepared amorphous ZnO and TiO₂ surface structures and subsequently studied their chemical reactivity by exposing them to a variety of small molecules, in particular, water and small organic molecules. The amorphous structures were generated by melt-quench simulations starting from randomly positioned metal and oxygen atoms in a supercell. The volume of the supercell was adjusted such that the experimental density of ZnO and TiO₂ was reproduced. A special new technique was developed that allows to create amorphous surface structures in a direct way without the need to cleave amorphous bulk configurations. First results for the interaction of water and acetic acid with the amorphous surfaces will be shown and will be compared to their behavior on the crystalline counterparts.