1. Institute
of Particle Technology, Friedrich-Alexander Universität Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
2. Department
of Materials Science and Physics, University of Salzburg, Hellbrunnerstrasse
34/III, A-5020 Salzburg, Austria
3. Institut
des Nanosciences de Paris, UMR7588, CNRS, 4 place Jussieu, 75252 Paris, Cedex 05, France
4. INSP,
UMR 7588, UPMC − Université Paris 06, 4 place Jussieu, 75252 Paris, Cedex 05, France
5. Department
of Applied Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden