Controllable synthesis of graphene oxide–silver (gold) nanocomposites and their size-dependencies

Recently, graphene/graphene oxide-based metal composites have opened up an exciting new field in science and technology. From a synthetic point of view, it is highly attractive with controllable synthesis of graphene/graphene oxide-based metal composites. We present here a facile synthesis of graphene oxide (GO) with noble metal (Ag, Au) nanoparticles by mixing GO and metallic nanoparticles in a water-n-butylamine system for controlled local size and properties. The structural details and textural properties of these resultant GO-Ag and GO-Au composites were characterized by X-ray diffraction, transmission electron microscopy, UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy analysis. The Raman scattering and catalytic experimental results showed that these GO-metal composites exhibit some size-dependencies. The Raman enhancement from GO-Ag samples increased as the Ag nanoparticles size was increased, whereas the catalytic activity of the GO-Au samples decreased in the oxidation of ethylene glycol as the size of Au nanoparticles was increased. This synthetic strategy is generalized and is expected to be applied to decorate GO with a multitude inorganic nanoparticles with desired particle sizes, shapes and properties.