Methanol-Tolerant Oxygen Reduction Reaction at Pt–Pd/C Alloy Nanocatalysts

Carbon-supported platinum and Pt–Pd alloy electrocatalysts with different Pt/Pd atomic ratios were synthesized by a microemulsion method at room temperature (metal loading is $10wt%$⁠). The Pt–Pd/C bimetallic catalysts showed a single-phase fcc structure and the mean particle size of Pt–Pd/C catalysts was found to be lower than that of Pt/C. The methanol-tolerant studies of the catalysts were carried out by activity evaluation of oxygen reduction reaction (ORR) on Pt–Pd catalysts using a rotating disk electrode (RDE). The studies indicated that the order of methanol tolerance was found to be $PtPd3/C>PtPd/C>Pt3Pd/C$⁠. The oxygen reduction activities of all Pt–Pd/C were considerably larger than that of Pt/C with respect to onset and overpotential values. The Pd-loaded catalysts shift the onset potential of ORR by $125mVMSE$⁠, $53mVMSE$⁠, and $41mVMSE$ to less cathodic potentials for $Pt3Pd/C$⁠, PtPd/C, and $PtPd3/C$⁠, respectively, with reference to Pt/C and the $Pt3Pd/C$ catalyst showed greater shift in the onset value than the other PtPd catalysts reported in literature. Moreover, the Pt–Pd/C catalysts exhibited much higher methanol tolerance during ORR than the Pt/C, assessing that these catalysts may function as a methanol-tolerant cathode catalysts in a direct methanol fuel cell.