(a)  (d) (b)  (e) (c)  (f)  Figure 1.SEM images of three catalyst layers with an ionomer content of 30 wt.% and a platinum loading of (a) 0.08 mg cm−2 (1 Layer), (b) 0.180 mg cm−2 (2 Layers) and (c) 0.271 mg cm−2 (3 Layers) with the corresponding carbon, fluorine and platinum distributions given in (d) 1 layer, (e) 2 layers and (f) 3 layers: red corresponds to carbon, green corresponds to fluorine and turquoise to platinum.