Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Focus Session: Structure and Chemistry of Metal-Oxide Surfaces II
O 55.6: Vortrag
Mittwoch, 14. März 2018, 11:45–12:00, MA 005
Adsorption of formic acid on the (001) surface of Fe3O4 studied by surface x-ray diffraction — •Björn Arndt1,2, Marcus Creutzburg1,2, Vedran Vonk1, Elin Graanaes1, Konstantin Krausert1,2, Kai Sellschopp3, Gregor Feldbauer3, Heshmat Noei1, and Andreas Stierle1,2 — 1Deutsches Elektron-Synchrotron (DESY) — 2University of Hamburg — 3Institute of Advanced Ceramics, Hamburg University of Technology
The clean (001) surface of magnetite shows a (√2x√2)R45∘ surface reconstruction which gets lifted by certain adsorbates, one of them being formic acid. Although the structure of the reconstructed surface is solved with all evidence supporting the SCV model [1,2], the structure of the unreconstructed surface and the lifting mechanisms are still unknown. Formic acid allows the preparation of a nicely defined surface since it only adsorbs up to a coverage of two molecules per unit cell [3]. It also raises interest as a intermediate in the water-gas shift reaction which magnetite catalyzes, and as a model for the surface interaction of longer organic acids with magnetite. In order to get information on the structure of the surface after formic acid adsorption, we investigated it by surface x-ray diffraction measured at the ID03 beamline of the ESRF before and after dosing of formic acid. We present our results on the structure of the unreconstructed surface, compare them to DFT calculations and give insights into the lifting mechanism.
[1] Bliem, R. et al. Science. 346, 1215-1218 (2014)
[2] Arndt, B. et al. Surf. Sci. 653, 76-81 (2016)
[3] Gamba, O. et al. J. Phys. Chem. C 119, 20459-20465 (2015)