Recent studies of the PEMFC catalytic layer electrocatalystsupport showed that high surface area carbon blacks cannot beused efficiently (1) because they have necessarily small primarypores that yield high diffusion limitation for the oxygenreduction reaction (ORR). In the present paper, we firstsynthesized and characterized carbon aerogels which exhibit highsurface area, high porous volume and adjustable pore-sizedistribution. In that way, they enable to decouple betweensurface area and porosity, while they are also promisingelectrocatalyst supports (2). Second, we elaborated newcatalytic layers made from 2 different carbon aerogels with 2different Nafion loadings. Finally, we characterized thestructure of such catalytic layers, and evaluated their activitytowards the oxygen reduction reaction (ORR). Finally, anappropriate catalyst support should display large pore-size andhigh surface area in order to reduce the PEMFC cathode platinumloadings without loosing activity, following the reduction ofoxygen diffusion limitation.