1. Electron Microscopy Center, Empa – Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
2. Nanomaterials Lab, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK
3. Department of Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-41296 Göteborg, Sweden
4. Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland