Synthesis of reduced graphene oxide by gamma irradiation

Abstract

Graphene is a 2D carbon-based nanomaterial that has a high specific surface area with remarkable physical and chemical properties. These unique properties make graphene a nanomaterial with wide electrochemical applications. However, it is not possible to functionalize graphene sheets and increase their field of application because there are no organic functions in their surface. So, an important precursor of graphene, graphene oxide (GO), then contains oxygen functional groups on the surface is been using functionalized. Partial reduction of graphene oxide leads to reduced graphene, a nanomaterial that combines both properties of graphene and graphene oxide: an excellent electrical and thermal conductivity and remaining oxygen groups that allow its functionalization. In the literature it is described many ways to produce reduced oxide graphene from graphene oxide, such as chemical reduction using hydrazine hydrate or NaBH4 or thermal reduction using high temperatures. Here in it is described an attractive and green process to reduce graphene oxide in aqua solution using gamma radiation. Exfoliated graphene oxide (1-100mg / L) under inert medium was submitted to gamma radiation. The radiation dose ranged from 20 to 80 kGy and the product was centrifuged. The characterization was performed by X-Ray Diffraction (XRD), Infrared Spectroscopy (ATR-FTIR) and Thermogravimetric analysis (TGA). The XRD results demonstrated characteristic diffraction peaks at about 10° and 25° corresponding to GO and Graphene, respectively, indicating the rGO formation. ATR-FTIR showed the characteristic peaks of functional groups (epoxy, hydroxyl and carboxyl) for GO. After the gamma irradiation, it was noticed a reduction at the intensity of the peaks at of carboxyl/carbonyl an increase at aromatic carbon bond. TGA analysis indicated a decrease of the oxygen groups.