Wenoticed that the major diffraction peaks of PtxCo1−xcatalysts aregradually shifted to higher 2 angles with increasing Co content(Table 1). This indicates a contraction of the lattice and confirmsthe formation of Pt–Co alloys due to the incorporation of Co intothe fcc crystal structure of Pt.The morphologies of the as-prepared Pt0.7Co0.3alloy catalystsdeposited on Vulcan XC-72 carbon matrix were observed by FEG-SEM. Fig. 1B shows a SEM image of a typical Pt0.7Co0.3alloy