1. Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE) University of Duisburg-Essen 45141 Essen Germany
2. Instrumental Analytical Chemistry University of Duisburg-Essen 45141 Essen Germany
3. EPR Research Group Max Planck Institute for Chemical Energy Conversion 45470 Mülheim an der Ruhr Germany
4. ICAN University of Duisburg-Essen 47057 Duisburg Germany
5. Faculty of Physics University of Duisburg-Essen 47057 Duisburg Germany
6. Institut für Geologie Mineralogie und Geophysik Ruhr-Universität Bochum 44780 Bochum Germany
7. Laboratory of Industrial Chemistry Faculty of Chemistry and Biochemistry Ruhr-Universität Bochum 44780 Bochum Germany