1. Nanoparticle Process Technology, University of Duisburg-Essen, Duisburg 47057, Germany
2. Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Duisburg 47057, Germany
3. Laboratory of Industrial Chemistry, Ruhr University Bochum, Bochum 44780, Germany
4. Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany