High performance PtPdAu nano-catalyst for ethanol oxidation in alkaline media for fuel cell applications

In the present investigation, Vulcan XC-72 supported Pt and Pt based binary and ternary catalysts (Pt/C, PtPd/C, PtAu/C, PtPdAu/C) have been synthesized under borohydride reduction scheme and applied for the study of the electro-oxidation of ethanol in alkaline media at room temperature. The surface morphology of the catalysts was determined by xRD (X-ray diffraction) & TEM (transmission electron microscopy) analysis. XRD patterns reveal that all the catalysts have disordered face center cubic lattice structures. Low resolution TEM images reveal uniform dispersion of metal nano particles on carbon support having an average size of 3-4.5 nm. HRTEM is also carried out for the determination of the distance between the lattice planes. Different textural properties including external surface area, pore volume and widths of the catalyst matrix were calculated by applying the BET equation to the adsorption isotherms. During electrolysis substantial increase in anodic peak current was observed for ethanol oxidations when the second and third metal component was introduced into the Pt matrix as in case of PtPdAu/C catalysts. The charge transfer resistance (12,,) for ethanol oxidation was substantially reduced from 87.90 on Pt/C to 7.74 Omega on PtPdAu/C demonstrating the superior electrode kinetics behavior of the latter over the other catalysts studied. Thus Au and Pd incorporation into the Pt matrix not only increases the catalytic efficiency of the alloyed catalyst but at the same time effectively reduces the Pt content in the ternary system. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.