SO2 and CO are detrimental agents to Pt based catalysts applied in proton exchange membrane (PEM) fuel cells. We introduce low-content (2, 4, and 6 wt%) amorphous cerium oxide (CeO2) to modify Pt catalysts for enhancing the SO2 and CO tolerance. The structure and morphology of the catalysts are studied by XRD, TEM and XPS analyses. Electrochemical results show that 2 wt% of CeO2 in the Pt/C catalyst exhibits the best SO2 poisoning resistance, while CO tolerance is enhanced as increasing content of CeO2. The promotional effect of Pt-CeO2/C catalysts on SO2 and CO poisoning resistance is also discussed. (C) 2013 Elsevier Ltd. All rights reserved.