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Abstract: In this study, a novel core–shell structured Pd3Fe@Pt/C electrocatalyst, which is based on Pt deposited onto carbon supported Pd3Fe nanoparticles, is prepared for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The carbon supported Pd3Fe nanoparticles act as seeds to guide the growth of Pt. The formation of the core–shell structured Pd3Fe@Pt/C is confirmed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrochemical characterization. The higher surface area of the synthesized catalyst suggests that the utilization of Pt in the Pd3Fe@Pt/C catalyst is higher than that in Pt/C. Furthermore, better electrocatalytic performance than that of Pt/C and Pd3Fe/C catalyst is observed in the ORR which follows a four-electron path. Consequently, the results indicate that the Pd3Fe@Pt/C catalyst could be used as a more economically viable alternative for the ORR of PEMFCs. [Copyright &y& Elsevier]

Abstract: A solution-phase synthesis method was studied to prepare carbon supported Pt-Co alloy catalysts. The organic precursors of Pt acetylacetonate and Co acetylacetonate were reduced in a high boiling point solvent of octyl ether in the presence of oleic acid (OAc) and oleylamine (OAm) to produce fine Pt-Co nanoparticles, which were subsequently deposited on carbon support to obtain Pt-Co/C catalysts. Thermogravimetric analysis suggests that the stabilizers (OAc and OAm) can be removed by copious ethanol washing and subsequent moderate temperature heat-treatment (250°C, under Argon atmosphere). X-ray diffraction patterns indicate that the average particle size is around 2.3nm, and the lattice parameter is 3.868Å for the heat-treated Pt-Co/C (40wt%). Transmission electron microscopy images show very small Pt-Co alloy nanoparticles homogeneously dispersed on the carbon support with a particle size distribution of 2–4nm for all Pt-Co/C samples. The elements composition of Pt and Co in the final Pt-Co/C catalyst can be well controlled, as evidenced by inductively coupled plasma atomic emission spectroscopy and energy dispersive spectroscopy analyses. Proton exchange membrane fuel cell tests show the heat-treated Pt-Co/C cathode catalyst has higher mass activity of oxygen reduction reaction than Pt/C at an operation voltage of 0.9V, this can be attributed to its smaller particle size and reduced lattice parameter. [Copyright &y& Elsevier]