1. Technical University of Munich, School of Natural Sciences, Department of Physics, Professorship of Physics of Energy Conversion and Storage, 85748 Garching, Germany
2. BMW AG, Petuelring 130, 80809 München, Germany
3. Technical University Braunschweig, Faculty of Mechanical Engineering, Institute of Internal Combustion Engines and Fuel Cells, 38108 Braunschweig, Germany
4. Technical University of Munich, Catalysis Research Center TUM, Ernst-Otto-Fischer-Straße 1, 85748 Garching, Germany