▎ 摘　　要

In the present work, we have developed a method to achieve self-assembly of Au nanoparticles (NPs) on graphene sheets through chemical functionalization. Transmission electron microscopy and UV-Vis spectroscopy results indicate that the grafting density of Au NPs on graphene sheets can be controlled by changing the types of functional groups. The ability to control the density of Au NPs cannot be overestimated, because it provides tunable catalytic activity. These graphene/Au composites display good stability against agglomeration and show excellent catalytic activity in a model reduction reaction of 4-nitrophenol into 4-aminophenol. This study demonstrates a general approach to the preparation of tunable and reusable catalysts containing densely loaded and well dispersed Au NPs.