Preparation of polymeric modifier-attached graphene-supported bimetallic Pt-Pd nanocomposites, and their electrochemical properties as electro-catalysts

Graphene-supported bimetallic nanocomposites were synthesized by a modified sodium borohydride reduction method. Poly(diallyldimethylammonium chloride) (PDDA) was used as modifier for good dispersion and higher metal alloy content. The micro-structure and dispersive properties of the electro-catalysts were determined by X-ray diffraction, Fourier-transform-infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the Pt-Pd electro-catalysts were studied by cyclic voltammetry. This analysis confirmed that functional groups on the graphene oxide (GO) sheet were chemically bonded to the PDDA layer. The average particle diameter of Pt-Pd_{1 to 0.5}-PDDA-reduced graphene oxide (RGO) was found to be 2.4 ± 0.4 nm which is the smallest platinum metal particle size among Pt-Pd-PDDA-RGO electro-catalysts. The electrochemically active surface area was studied and the activity was found to be enhanced by use of the polymeric modifier.