The dissolution of Ru from the PtRu electrocatalyst has been identified as one of the most critical factors in degrading the performance of polymer electrolyte membrane fuel cells (PEMFC). In this work, we prepared an Au-modified PtRu catalyst (Au/PtRu) and found that the incorporation of Au could significantly stabilize the PtRu electrocatalyst against the dissolution of Ru. The X-ray photoelectron spectroscopy (XPS) characterization of the Au/PtRu catalysts revealed that the incorporation of Au increased the oxidation potential of Ru, which is the mechanism that leads to a reduction in the dissolution of Ru from the alloyed catalyst. The XPS characterization of the cathode catalyst also showed that with the PtRu as the anode catalyst Ru appeared at the cathode, but the crossover of Ru could be reduced when the anode catalyst was changed to Au/PtRu. (c) 2008 Elsevier B.V. All rights reserved.