Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 84: Poster Focus Session: Structure and Chemistry of Metal-Oxide Surfaces
O 84.4: Poster
Mittwoch, 14. März 2018, 18:15–20:30, Poster A
IRRAS studies of CO adsorption on well-defined iron oxide surfaces — •Ludger Schöttner, Alexei Nefedov, Chengwu Yang, Stefan Heissler, Yuemin Wang, and Christof Wöll — Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen
The interaction between CO and iron oxide (Fe2O3, hematite, and Fe3O4, magnetite) surfaces is of great interest because of its applications in heterogeneous catalysis and industrial processes such as carbothermic iron ore reduction. In addition, CO is the simplest heteronuclear diatomic molecule and is widely used in infrared spectroscopy (IR) to probe the local structure of catalyst surfaces. In this work the adsorption of CO on various iron oxide monocrystalline surfaces was studied using polarization-dependent IR reflection absorption spectroscopy (IRRAS). Based on the IRRAS results, it was established that the stoichiometric surface of Fe2O3(0001) is terminated with Fe3+, as observed for the Fe3O4(001) surface. On the Fe3O4(111) surface two vibrational CO bands were detected which correspond to Fe3+ and Fe2+ species, respectively. It was found that after reduction the hematite (0001) surface is converted to the more stable magnetite (111) structure. Moreover, the magnetite (111) facets were identified as a primary topology on the reconstructed Fe3O4(110) surface.