Ceria nanoparticles were added to the electrodes of proton exchange membrane fuel cells as free-radical scavengers to minimize the degradation of membrane electrode assembly (MEA) components. Accelerated durability tests were performed at low humidity under open circuit voltage (OCV) conditions, and the results were compared with traditional MEAs without CeO2. Gas crossover was monitored during the durability test, and the MEAs were examined by SEM before and after the durability test. The results showed that adding CeO2 as free-radical scavengers to the electrode greatly improves the chemical stability of the membrane. The degradation rate of the MEA with CeO2 in the anode was similar to that of the MEA with CeO2 in the cathode. The fuel cell with CeO2 in the cathode showed better MEA performance that the fuel cell with CeO2 in the anode. (C) 2013 Elsevier Ltd. All rights reserved.