In this paper, Pt-Pd/C and Pt/C catalysts were evaluated and compared. The catalysts were evaluated as oxygen reduction reaction (ORR) catalysts in half cell test under potential cycling, and cathode catalysts in single cell test under dynamic loading simulating the vehicle operation. Physical and electrochemical techniques were applied to investigate the structure, performance and durability of those catalysts. The electrochemical active surface area (ECA) loss, particle size distribution, polarization behavior and electrochemistry impedance spectroscopy (EIS) suggested that the Pt-Pd/C showed a better durability than Pt/C. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.