Platinum-palladium (Pt-Pd) bimetallic alloys have shown prospect as electrocatalyst for the oxygen reduction reaction (ORB.) in the cathode of polymer-electrolyte-membrane (PEM) fuel cells. This article reports a facile solvothermal synthesis of Pt-Pd bimetallic nano-dendrites (Pt-Pd NDs). The characterization with a variety of spectroscopic techniques indicates that the Pt-Pd NDs possess a three-dimensional (3-D) porous structure consisting of interconnected branches of highly alloyed Pt-Pd nanorods (NR). The measurements using rotating disk electrode in electrolyte solution show that the catalyst of Pt-Pd NDs supported on carbon (Pt-Pd NDs/C) possesses a Pt mass activity for ORR that is more than 3 times higher than that of the state-of-the-art Pt/C catalyst, as well as the significantly improved stability due to the branched porous structure. The measurements using membrane-electrode-assembly (MEA) in a single PEM fuel cell indicate the 3-D interconnected dendrite structures make the Pt-Pd NDs/C catalyst significantly advantageous over the nanoparticle Pt/C catalyst in reducing the mass transport and ohmic polarization which would become significant at high current density in MEA. (C) 2017 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.