The addition of Ir-based water electrolysis catalysts to the catalyst layer in polymer electrolyte membrane fuel cells was examined as a promising approach for preventing electrochemical carbon corrosion under severely corrosive conditions. Electrochemical carbon corrosion of membrane electrode assemblies containing different amounts of IrO2 or shape-controlled Ir dendrite catalysts were characterized using on-line mass spectrometry. In particular, Ir dendrite catalysts possess high activity toward oxygen evolution reactions when compared to IrO2. As a result, Ir dendrites provided a very effective method of removing water from the catalyst layer. Therefore, the addition of 1 wt% Ir dendrite (0.008 mg cm(-2)) to the catalyst layer of the cathode decreased electrochemical carbon corrosion by 84% at 1.6 V-NHE compared with a conventional membrane electrode assembly in the absence of water electrolysis catalysts. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.