1. Institute
of Physical Chemistry and Electrochemistry, and ZFM − Center
for Solid State Chemistry and New Materials, Leibniz University Hannover, Callinstr. 3-3a, 30167 Hannover, Germany
2. Deutsches Elektronensynchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
3. Institute
of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz
1, D-76344 Eggenstein-Leopoldshafen, Germany