Size-controllable self-assembly of metal nanoparticles on carbon nanostructures in room-temperature ionic liquids by simple sputtering deposition

We report a generic strategy to make hybrids incorporating metal nanoparticles and carbon nanosupports with large surface area, which is a one-step, universal approach totally free of additives and by-products. Utilizing this approach, we show that small Au, Ag and Pd nanoparticles of uniform size can be self-assembled on diverse carbon nanostructures such as graphene oxide, reduced graphene oxide, and multiwalled carbon nanotubes by simply sputtering metal onto room-temperature ionic liquids. The size of metal nanoparticles can be controlled by the composition of room-temperature ionic liquids, and the surface density of metal nanoparticles can be controlled by the sputtering conditions. The self-assembly is demonstrated to be driven by the interlinking interactions among the metal nanoparticles, ionic liquid cations and carbon nanostructures.