As the worm-like structures indicated that there might be an impact on the sample surface, BET measurements using krypton gas were performed for the nanocomposite 5d and the corresponding bulk material for comparison at 77 K. Before measurement, the samples were heated to 100 °C under vacuum for 6 h. With 5.5 m 2 g -1 for the bulk and 4.0 m 2 g -1 for the composite, similar values were obtained. Thus the structures in Figure and Figure are only 2D structures and no additional porosity is introduced yet. This challenge will be addressed in future research.