Development of Functionalized Graphene Supported Highly Durable Pt-Free Bi-metallic Electrocatalysts for PEMFC

Author(s): Avijit Ghosh

Functionalized graphene supported Pt-free single metallic (Pd/FGP or Au/FGP) and bimetallic (PdAu/FGP) electrocatalyst were synthesized using NaBH4 reduction techniques. The electro-catalytic activity of developed Pd/FGP, Au/FGP, and PdAu/FGP were investigated x-ray powder diffraction (XRD), transmission electron microscopy (TEM), oxygen reduction reaction (ORR), and cyclic voltammetry (CV). The performance of the developed bimetallic electrocatalyst was compared with the commercial Pt/C. The oxygen reduction of PdAu/FGP was started gradually at a potential around 1.0 V and reached a limiting plateau at a potential around 0.75 V. Though the 50% Pd was replaced by Au but the ORR performance of the PdAu/FGP is almost maintained. The similar electro-catalytic activity of the Pd and/or PdAu can also be explained based on the synergetic effect of the Au and Pd in ORR. The active electrochemical surface area (ESA) is measured using CV analysis. The ESA for the Pd/FGP, PdAu/FGP, and Pt/C were found to be around 63.32, 51.27, and 43.4 m2•g-1Pt, respectively. The single cell polymer electrolyte membrane fuel cell (PEMFC) power density of the Pd/FGP, PdAu/FGP, and Pt/C were found to be 439, 414, 373 mW.cm-2, respectively. The developed bimetallic (PdAu/FGP) electrocatalys shows significantly higher stability under ORR test as compared to commercial Pt/C.