Effects of reduction time on the structural, electrical and thermal properties of synthesized reduced graphene oxide nanosheets

The reduction of graphene oxide (GO) nanosheet is a promising route to produce a stable colloidal dispersion of reduced graphene oxide (RGO) nanosheets in a large scale. The production of RGO nanosheet is one of the important topics in nanotechnology disciplines due to its contribution in various applications, such as the platinum catalyst support in direct methanol fuel cell. Therefore, in this paper, the RGO nanosheets were prepared via highly efficient chemical reduction reaction of exfoliated GO nanosheets using sodium oxalate (Na2C2O4) as the reducing agent. Extensive characterizations have been conducted in terms of structural, thermal stability and electrical conductivity properties by means of high-resolution transmission microscopy, the Fourier transform infrared spectroscopy, UV-visible spectroscopy, 13C NMR and four-point probe conductivity measurement. The results indicate that most of oxygen-containing functional groups from GO nanosheets have been removed and the RGO-3 possess greater thermal stability compared to GO nanosheets. The prepared RGO-3 shows the highest electrical conductivity at room temperature which is ~2.0 × 103 S m-1. Based on these analyses, the plausible mechanism of reduction of GO to RGO by sodium oxalate is well proposed