Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 43: Oxides and Insulators: Adsorption I
O 43.2: Vortrag
Dienstag, 8. März 2016, 14:15–14:30, H6
Adsorption of water on the (001) surface of Fe3O4 studied by surface x-ray diffraction — •Björn Arndt1, 2, Heshmat Noei1, Roland Bliem3, Oscar Gamba3, Gareth Parkinson3, Ulrike Diebold3, and Andreas Stierle1,2 — 1Deutsches Elektron-Synchrotron (Desy), D-22607 Hamburg, Germany — 2Fachbereich Physik, Universität Hamburg, D-20355 Hamburg, Germany — 3Institute of Applied Physics, Vienna University of Technology, 1060 Vienna, Austria
Magnetite (Fe3O4) exhibits interesting properties which makes it attractive for applications e.g. in catalysis, where it is used to catalyze the water-gas shift reaction. The (001) surface of magnetite shows a (sqrt(2)x sqrt(2))R45° surface reconstruction in UHV [1], which gets lifted upon adsorption of water vapor at room temperature. Previous studies of the adsorption of water at different coverages on this surface were done by XPS measurements [2], without linking it to the surface structure. To probe the unreconstructed surface structure, we therefore performed surface x-ray diffraction at the ESRF ID03 beamline under flow conditions at a photon energy of 11 keV and at the MPG diffraction beamline at ANKA under static conditions at 10 keV and water vapor pressures in the mbar regime at room temperature. We were able to follow the lifting of the surface reconstruction and observed changes in the morphology of the surface. Crystal truncation rod data give insight into the surface structure. 1. Bliem et al., Science, 346, 1215-1218 (2014) 2. Kendelewicz, T. et al., J. Phys. Chem. C 117 , 2719-2733 (2013)