The present work describes the potential of a hybrid carbon hetero-structure having the unique properties of one-dimensional carbon nanotubes and two-dimensional graphene as a catalyst support material for platinum-free electrocatalysts in polymer electrolyte membrane fuel cell (PEMFC) for hydrogen oxidation reaction (HOR) or oxygen reduction reaction (ORR). Partially exfoliated carbon nanotubes (PCNT), which have the synergistic effect of good electrical conductivity and high surface area, have been used as the support material for Pd3Co alloy catalysts. This provides more active sites for the dispersion of catalyst particles along with quick electron transport through the carbon structure. This unique characteristic increases the catalytic activity of the electrocatalysts. The electrochemical half-cell studies confirm that, ORR on Pd3Co/PCNT proceeds via a four-electron process. The single cell measurements were carried out by preparing a membrane electrode assembly (MEA) using Pd3Co/PCNT at the anode, cathode separately as well as simultaneously at both the anode and cathode. A maximum power density of 327 mW cm(-2), 240 mW cm(-2) and 96 mW cm(-2) is attained from the use of Pd3Co/PCNT nanocomposite at anode, cathode and at both electrodes simultaneously in a PEMFC at 60 degrees C, respectively. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.