Universal Method for Producing Reduced Graphene Oxide/Gold Nanoparticles Composites with Controlled Density of Grafting and Long-Term Stability.

Szustakiewicz Szustakiewicz,Lewandowski Lewandowski,Kołsut Kołsut,Leniart Leniart

doi:10.3390/nano9040602

Szustakiewicz Szustakiewicz, Lewandowski Lewandowski + Show 2 more

Open Access

https://doi.org/10.3390/nano9040602

Copy DOI

Abstract

In this study, we report a universal approach allowing the non-covalent deposition of gold nanoparticles on reduced graphene oxide surface in a controlled fashion. We used a modified Hummers method to obtain graphene oxide, which then underwent surficial functionalization with carboxyl moieties coupled with simultaneous reduction. Nanoparticles were synthesized ex-situ and capped with a thiolated poly-ethylene glycol (PEG) ligand. The interactions between the surface of modified graphene oxide and nanoparticle ligands enabled the formation of stable hybrid graphene-nanoparticles materials in the aqueous phase. Using this technique, we were able to cover the surface of graphene with gold nanoparticles of different shapes (spheres, rods, triangles, stars, and bipyramids), broad range of sizes (from 5 nm to 100 nm) and controlled grafting densities. Moreover, materials obtained with this strategy exhibited long-term stability, which coupled with the versatility and facility of preparation, makes our technique appealing in the light of increasing demand for new graphene-based hybrid nanostructures.

Highlights

In 2004, Novoselov et al [1] isolated and characterized single-layered graphene from graphite, giving rise to a new field of research—2D materials
In this study, we report a universal approach allowing the non-covalent deposition of gold nanoparticles on reduced graphene oxide surface in a controlled fashion
Two mixtures in vials were prepared: (1) 1.6 mL of 50 mM HAuCl4 solution was added to 6.4 mL of 100 mM CTAC solution in 32 mL of Milli-Q water; and (2) 2.35 mL of 10 mM NaI solution was added to solution containing 3.91 mL of 50 mM HAuCl4 and 313 mL of 50 mM CTAC

Summary

Introduction

In 2004, Novoselov et al [1] isolated and characterized single-layered graphene from graphite, giving rise to a new field of research—2D materials. Along with high application potential, have led to the development of various techniques of preparing G/NP composite materials, which can be divided into two main categories: (1) an in-situ approach, in which nanoparticles are grown directly on a graphene/graphene derivative surface, offers fast and efficient method of decorating graphene. The downside of these methods is limited control over the size, shape and distribution of the nanoparticles [4]; and (2) an alternative ex-situ approach, in which nanoparticles are synthesized separately and deposited onto a graphene surface. We show that the performed chemical modifications ensure non-covalent interactions between nanomaterials, which enabled us to deposit various types of nanoparticles onto graphene’s surface in a controlled manner

Materials

Ligand Exchange Process

2.13. Nanoparticle Density Analysis

2.14. Structural Analyses of Composite Materials

Carboxyl-Modified Reduced Graphene Oxide

Conclusions