Pd Octahedral and Spherical Nanocrystals Supported on Crumpled Graphene Oxide: Their Comparative Studies for Electrocatalytic Applications

Abstract

Palladium (Pd) octahedral and spherical nanocrystals (NCs) were successfully synthesized on crumpled graphene oxide (GO) by surface adsorption of H2 and CO in the presence of capping agent poly(vinylypyrrolidone) (PVP). Their comparative studies as anode material for direct methanol fuel cells (DMFCs) have been measured by hydrogen evolution reaction (HER) performance and methanol oxidation reaction (MOR) activity. The electrocatalytic properties of both the nanocrystals were studied in HClO4 acidic media and com-pared with each other. Pd octahedral nanocrystals have shown the best performance as an anode material, their onset potential for evolu-tion of hydrogen from the active sites of the catalyst is more towards zero than the spherical NCs. The observed specific activity (ca. 4.3 mA.cm-2) and mass activity (ca. 5300 mA.mg-1) of Pd towards MOR is much higher for octahedral NCs than that of spherical NCs.