Nanostructured Pt and Pt3Co cathodes for proton exchange membrane fuel cells (PEMFCs) have been prepared by pulse electrodeposition. For high utilization the catalyst nano particles are directly deposited on the microporous layer (MPL) of a commercial available gas diffusion layer (GDL). In order to increase the hydrophilic nature of the substrate surface and thus improve drastically the electrodeposition process and the fuel cell performance, prior to electrodeposition, the carbon substrate is submitted to O-2/Ar plasma activation. Cathodes with different amounts and distributions of Aquivion ionomer within the cathode catalyst layer (CCL) thickness ("homogeneous", "gradient" and "anti-gradient"), different catalysts (Pt and Pt3Co) at varied plasma duration and catalyst loading have been prepared. The cathodes are analysed via attenuated total reflection (ATR-IR), goniometer, SEM, 0.5 M H2SO4 half-cell and 25 cm(2). H-2/Air single PEMFC. The highest single fuel cell performance is obtained for 2 min plasma activated Pt3Co cathode. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.