Pd-on-Au Supra-nanostructures Decorated Graphene Oxide: An Advanced Electrocatalyst for Fuel Cell Application.

We report a very easy and effective approach for synthesizing unique palladium-on-gold supra-nanostructure (Au@Pd-SprNS)-decorated graphene oxide (GO) nanosheets. The SprNSs comprising Au nanorods as core and a unique close-packed assembly of tiny anisotropic Pd nanoparticles (NPs) as shell were homogeneously distributed on the GO surface via electrostatic self-assembly. Compared with the traditional one-pot method for synthesis of metal NPs on GO sheets, the size and shape of core-shell Au@Pd SprNSs can be finely controlled and uniformly distributed on the GO carrier. Interestingly, this Au@Pd-SprNSs/GO nanocomposite displayed high electrocatalytic activities toward the oxidation of methanol, ethanol, and formic acid, which can be attributed to the abundance of intrinsic active sites including high density of atomic steps, ledges and kinks, Au-Pd heterojunctions and cooperative action of the two metals of the SprNSs. Additionally, uniform dispersion of the SprNSs over the GO nanosheets prevent agglomeration between the SprNSs, which is of great significance to enhance the long-term stability of catalyst. This work will introduce a highly efficient Pd-based nanoelectrocatalyst to be used in fuel cell application.