Gold nanoparticle-doped graphene nanosheets: sub-nanosized gold clusters nucleate and grow at the nitrogen-induced defects on graphene surfaces

We report the theory and synthesis of sub-nanosized gold clusters on reduced graphene oxide (r-GOs). The Au sub-nanoclusters were found to be nucleated and grown at defects of the r-GOs, particularly on nitrogen-induced defects from density functional theory investigation. The resulting Au/r-GOs exhibit an improvement of bulk electrical conductivities and a reduced ratio of the intensity of the D band to that of the G band (I-D/I-G), compared to the r-GOs without Au nanoclusters. The unique decrease of the I-D/I-G was demonstrated to be related to the filling of subnano-sized Au clusters on the r-GOs, presumably owing to enhancing the flat geometry of the graphene nanosheets.