Hollow flower-like AuPd alloy nanoparticles: One step synthesis, self-assembly on ionic liquid-functionalized graphene, and electrooxidation of formic acid

A novel hollow AuPd (hAuPd) alloy nanostructure with a rough surface was fabricated via a facile one-pot simultaneous reduction of Au(III) and Pd(I) and then assembled on ionic liquid-grafted graphene sheets by electrostatic interaction to form graphene–metal hybrid nanomaterials under mild conditions. The resulting hollow alloy nanostructure and graphene nanocomposites were then characterized using many techniques, such as transmission electron microscopy (TEM), high-resolution TEM (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), element analysis mapping, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), confirming that the alloy nanoparticles with hollow cores had been successfully synthesized by one step galvanic replacement and attached firmly onto the graphene sheets. The electrocatalytic ability of the resulting nanocomposites for direct oxidation of formic acid was also explored. The hollow AuPd alloy nanospheres, especially the graphene-supported nanocomposites, exhibited striking electrocatalytic activities which show potential application in fuel cells.