Furthermore, EELS allows for the separation of the Co oxidation state as particularly the L3 intensity (in correlation to the L2 intensity) directly correlates with the number of unoccupied 3d states and is thus a measure for the change in Co oxidation state. The seed-layer particles and active catalyst material show a higher, but mixed oxidation state of Co (Fig. ) in comparison to the nanosheets. That higher mean oxidation state is not necessarily reflected in an increased L3/L2 ratio of the respective peak heights but in a significantly broader L3 peak (and thus intensity).