Figure 13.

Functionalization of spongin fibers for the development of a 3D structured catalyst. The spongin fibers (A) can be effectively carbonized under a nitrogen-rich atmosphere and tightly covered with a manganese oxide layer (B). The carbonized spongin became visible only on the mechanically damaged surface, with the surface of the fibers covered with the oxide (arrow). The formation of a secondary Mn oxide nanocrystalline phase can also be observed (C, D).