Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 78: Poster: Surface Dynamics - Reactions, Elementary Processes and Phase Transitions
O 78.14: Poster
Mittwoch, 14. März 2018, 18:15–20:30, Poster A
Observing oxide surface reactivity at high temperatures: FastSTM on Fe3O4(001) — •Alexander Bourgund, Barbara A. J. Lechner, Ueli Heiz, and Friedrich Esch — Department of Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, D-85748 Garching
Magnetite as a highly abundant oxide material shows a rich surface chemistry and is a well-known support for nanoparticles in catalysis [1]. While its surface dynamics have been studied extensively with conventional Scanning Tunneling Microscopy (STM) and other techniques [1-3], little is known about these surface processes at the atomic scale when studied at elevated temperatures, with the required high temporal resolution. We present results on magnetite Fe3O4(001) surface dynamics taken with a specially developed FastSTM add-on module [4] that boosts the temporal resolution of our commercial STM up to 12 frames/s. In particular, we resolve subsurface diffusion of iron atoms and their exchange with the bulk at temperatures up to 800 K and provide additional insight into the high-temperature transition [3]. Furthermore, we observe surface etching under reducing or wet conditions, as well as growth in an oxygen atmosphere. The reactivity of the surface can be enhanced by deposition of Pt10 clusters that lower the reaction onset temperature.
References: [1] G. S. Parkinson, Surf. Sci. Rep. 2016, 71, 272. [2] R. Bliem et al., Angew. Chem. Int. Ed. 2015, 54, 13999. [3] N. C. Bartelt et al., Phys. Rev. B 2013, 88. [4] F. Esch et al., Rev. Sci. Instrum. 2011, 82, 53702 and NFFA project JRA1.