Assembly of gold nanoparticles on graphene film via electroless deposition: spontaneous reduction of Au3+ ions by graphene film

Abstract

In this paper, an electrochemically reduced graphene oxide–gold nanoparticle (ERGO–AuNP) composite film was fabricated on a glassy carbon electrode (GCE) by a simple electroless deposition method using a solution containing HAuCl₄ and NH₂OH. The deposition of AuNPs on the ERGO film was achieved via two different approaches. The first approach involves the electroless deposition of AuNPs on the graphene oxide (GO) modified GCE followed by the electrochemical reduction. The second approach is the electroless deposition of AuNPs on the ERGO film modified GCE which was fabricated by self-assembling GO on a 1,6-hexadiamine modified GCE followed by the electrochemical reduction. The particle coverage estimated from cyclic voltammetry (CV) showed that the particle coverage of AuNPs deposited on the ERGO film (22%) was higher than that of the GO film (17%) and bare GCE (7%) under identical conditions. The obtained higher coverage is attributed to the ERGO film's ability to spontaneously reduce Au³⁺ ions. Although AuNP deposition was observed at the ERGO surface in the absence of NH₂OH, the particle coverage was much less (2%) and hence the electroless deposition was carried out in the presence of NH₂OH. SEM and CV studies showed that the particle coverage and density of AuNPs were increased while increasing the electroless deposition time.