Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 119: Oxides III: Single-Atom Catalysis, Iron Oxides
O 119.4: Talk
Friday, March 20, 2020, 11:30–11:45, REC C 213
Influence of Surface Dynamics on Oxidation Processes: Case Study of H2Osurf Desorption on Fe3O4(001) — •Matthias Meier1,2, Jan Hulva1, Zdeněk Jakub1, Florian Kraushofer1, Manuel Ulreich1, Michael Schmid1, Ulrike Diebold1, Cesare Franchini2, and Gareth S. Parkinson1 — 1Institute of Applied Physics, TU Wien — 2Center for Computational Materials Science, Faculty of Physics, University of Vienna
Experiments performed under UHV, on so called "model systems", where surfaces are well defined and controlled, are combined with DFT calculations to propose reaction mechanisms and determine activation barriers of relevant chemical processes.
Fe3O4(001) is such a model system. It is debatable whether the observed surface in UHV is also maintained under real catalytic conditions, such as high pressure, or electrochemical environments. Our results indicate that the surface undergoes modifications, already in UHV and in some cases even below room temperature. O distortions and Fe displacements can occur for any given transition state along a reaction path, if energetically favored. So if their costs are at least compensated by the gain in adsorption energies of present adsorbates or the reduction of activation barriers.
We show here an example of how these surface dynamics influence H mobility, the formation and extraction of H2Osurf and their consequences on experimental observations.