A carbon-supported Palladium electrocatalyst was investigated for oxygen reduction and hydrogen oxidation in a polymer electrolyte fuel cell operating at intermediate temperatures (80-110 degrees C) and with low relative humidity (33%). A 30% Pd/C was synthesized by a colloidal method and subsequent carbothermal reduction. A mean particle size of 4.0 am and a homogeneous dispersion of Pd particles on the support were obtained. The performance of the Pd catalyst was compared to those obtained with a 50% Pt/C catalyst and a 50% Pt3Co1/C as anode and cathode, respectively. The Pd/C catalyst showed low over-potential for hydrogen oxidation whereas its performance as cathode was significantly lower than the benchmark Pt3Co1 catalyst. The main limiting effects for the Pd-based electrocatalyst appeared to be associated to a larger mean particle size compared to the benchmark Pt catalysts and to the modification of the carbon support during the synthesis procedure. These effects led to a stronger activation control, a slight increase of the series resistance and some diffusion constraints. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.