Relatore: Gregor Feldbauer Institute of Advanced Ceramics, Hamburg University of Technology.

Abstract

The adsorption of organic molecules on metal oxide surfaces is of high interest in diverse fields, ranging from environmental science to (photo-)catalysis and from biomedicine to material science. As a specific example, magnetite nanoparticles linked via organic acids are able to form hybrid materials exhibiting exceptional mechanical properties [1]. For such applications a detailed understanding of atomistic surface processes is crucial. Titania (TiO2) [2] and lately also magnetite (Fe3O4) [3] surfaces are widely used as model systems. Here, adsorption-related phenomena at such surfaces are investigated within the framework of density functional theory (DFT) and in close collaboration with experiments. In this talk, several examples of our work will be presented, including shape control during TiO2 nanoparticle synthesis, adsorption of acetone on a TiO2 surface [4], and the structure of the Fe3O4(001) upon adsorption. For the shape control, the influence of various adsorbates on the stability of TiO2 anatase surfaces is studied and the results are compared to TEM images. In the case of acetone adsorption, numerous adsorption geometries were calculated to scan the configuration space. Calculated IR spectra for adsorbed acetone and potential surface-reaction products are used to explain experimental results. For magnetite (001) surfaces, the implications of formic acid adsorption mainly on the surface structure are investigated computationally and the results are compared to experimental SXRD and IR data.