1. Institute
for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstr. 20, D-76131 Karlsruhe, Germany
2. Institute
of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
3. European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble Cedex, France
4. Center
for Functional Nanostructures and Institute of Physical Chemistry, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1a, D-76131 Karlsruhe, Germany