Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 24: Focus Session: Structure and Chemistry of Metal-Oxide Surfaces I
O 24.7: Talk
Tuesday, March 13, 2018, 12:45–13:00, MA 005
Coverage-dependent Water Agglomerates on Fe3O4(001): Insights from Experiments — •Zdenek Jakub1, Matthias Meier1,2, Jan Hulva1, Jiri Pavelec1, Martin Setvin1, Michael Schmid1, Ulrike Diebold1, Cesare Franchini2, and Gareth S. Parkinson1 — 1Institute of Applied Physics, TU Vienna, Austria — 2Faculty of Physics and Center for Computational Materials Science, University of Vienna, Austria
The interaction between iron oxides and water plays a key role in many natural and technological processes. Recent water adsorption studies have found significant complexity on metal oxides, with reports of mixed-mode adsorption and hydrogen bonding. Here we present a multi-technique study of water adsorption on Fe3O4(001) surface. Quantitative temperature programed desorption (TPD) and X-ray Photoelectron Spectroscopy (XPS) experiments reveal four partially dissociated phases in the submonolayer regime, corresponding to coverages of 9, 8, 6 and 3 molecules per surface unit cell. These are investigated by non-contact atomic force microscopy (nc-AFM) with tip functionalized by CO molecule. This approach is highly convenient to study water agglomerates on metal oxide surfaces, and we can clearly demonstrate the existence of dimers and trimers, and a complex hydrogen-bonded network at lower coverage. These images can be further interpreted by DFT-based calculations, which will be presented in a separate talk.