The performance of polymer electrolyte membrane fuel cells (PEMFCs) was reduced due to the degradation of the catalyst layer when reverse potential was generated by fuel starvation in PEMFCs. Detailed analysis was performed through accelerated reversal potential tests. The electrochemical impedance spectroscopy (EIS) measurement results showed that the charge transfer resistance increased and the electrochemical active surface area (ECSA) reduction was confirmed through the cyclic voltammetry (CV) measurements. Corrosion of the carbon used as the catalyst support was detected by confirming the CO peak in the 1st cyclic voltammogram in the CV measurements. Growth of the Pt catalyst due to the agglomeration and sintering of Pt was confirmed during increasing cycles of the accelerated reversal potential through X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.