Microscopic reaction steps on well-defined oxide surfaces
The studies are usually performed under UHV conditions using well-defined oxide substrates as models for real catalytic systems. Oxide surfaces may exhibit a notable complexity:
Typical research activities involve the characterization of the surface properties and the investigation of their role for reactions at the surface. Many studies are performed in co-operation with theory groups which is important in order to establish a consistent model.
- Structure and stoichiometry depend on temperature and oxygen pressure.
- Reactions at the surface can change the stoichiometry and the structure.
- Different types of defect states may be present.
- Polar surfaces may exhibit complex electrostatic stabilization mechanisms.
For our investigations we employ a number of experimental methods:
- High Resolution Electron Energy Loss Spectroscopy (HREELS) with an energy resolution of down to 1 meV and Infrared Reflection Absorption Spectroscopy (IRAS) for the investigation of vibrational and electronic excitations.
- Electron Energy Loss Spectroscopy (EELS) with medium energy resolution for the study of electronic excitations.
- Near Edge X-ray Absorption Fine Structure (NEXAFS), X-ray Photoemission Spectroscopy (XPS), and Angular Resolved Ultraviolet Photoelectron Spectroscopy (ARUPS) with synchrotron light and laboratory sources for the study of electronic properties, stoichiometry, oxidation states and adsorbate geometry.