1. Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
2. Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
3. Nanomaterials Lab, Swansea University, Bay Campus, Swansea, UK
4. National Centre for Nano Fabrication and Characterization, Technical University of Denmark, 2800 Kongens Lyngby, Denmark