PdPt bimetallic alloy nanoparticles with different atomic ratios of Pd and Pt were synthesized by it simple aqueous complexing-reduction method at room temperature. Ethylenediaminetetraacetic acid disodium salt was used as the complexing agent with Pd ions to enhance alloy formation for Pd and Pt atoms in nanoparticles at low temperatures. Both X-ray diffraction and transmission electron microscopy characterizations indicate that the sizes of the bimetallic alloy nanoparticles are ca. 2.6-3.8 nm, with a narrow size distribution and broad dispersion on it carbon support. Among the prepared catalysts, the PdPt/C alloy catalyst with all atomic ratio of 1:1 and heat-treatment at 150 degrees C exhibited a large electrochemical active surface area and it greater electrocatalytic activity for the oxygen reduction reaction (ORR); both measured results are found to be superior to that of the Pt/C catalyst acquired commercially. Most importantly, the Pd-Pt/C catalysts exhibited substantially higher methanol tolerance during the ORR than the Pt/C catalyst, ensuring it higher ORR performance while diminishing Pt Utilization. We find that the Pd-Pt/C bimetallic catalysts prepared by the approach developed herein may serve as methanol-tolerant cathode catalysts in a direct methanol fuel cell. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3176877] All rights reserved.