Surface Science Studies of an Iron Oxide Model Catalyst
Prof.Dr. Ulrike Diebold (head of the Surface Physics Group, Wien University)
Heterogeneous catalysts are notoriously complex materials, and obtaining mechanistic insights into processes occurring on their surfaces is often difficult. With surface science methods, in particular Scanning Tunneling Microscopy, one can follow dynamic mechanisms in an atom-by-atom fashion, albeit under very idealized conditions. In the talk, I will present recent studies of a ‘model catalyst’, i.e. well-defined metal nanoclusters supported on the flat surface of an iron oxide single crystal.
The Fe3O4(001) surface forms a reconstruction that stabilizes metals in the form of single, isolated atoms up to temperatures as high as 700 K. This resistance against thermal sintering is due to the special structure of the near-surface region. This property enables to identify gas-induced agglomeration processes and metal-catalyzed oxidation and reduction reactions that involve the support.