Palladium Decorated Polymer Functionalized Graphene for Enhanced Electrocatalytic Oxygen Reduction Reaction in Alkaline Fuel Cells

Newly synthesized Poly(3,4-ethylenedioxythiophene) functionalized graphene with palladium nanoparticles (denoted as Pd/PEDOT/rGO) has been introduced in electrochemical oxygen reduction reaction (ORR) for alkaline fuel cells (FCs). The structural features of catalyst are characterized by several instrumental techniques. The transmission electron microscopy (TEM) images suggest a well dispersed PdNPs onto PEDOT/rGO film. The ORR activity of Pd/PEDOT/rGO has been investigated via cyclic voltammetry and hydrodynamic voltammetry techniques in 0.1 M KOH aqueous solution. Comparative CV analysis suggests a general approach of intermolecular charge-transfer in between graphene sheet and PdNPs via PEDOT which leads to the better PdNPs dispersion and subsequently superior ORR kinetics. The Pd/PEDOT/rGO has superior electrocatalytic activity towards ORR than that of state-of-the-art Pt/C in respect to the half-wave potential and current density. Moreover, The mass activity of the Pd/PEDOT/rGO was measured as ~2 and ~9 times higher than that of Pt/C and Pd/rGO. The Koutecky–Levich and Tafel analysis suggest that the proposed main path in the ORR mechanism has direct four-electron transfer process with faster transfer kinetic rate on the Pd/PEDOT/rGO.