Preparation of RGO with Enhanced Electrical Conductivity: Effects of Sequential Reductions of L-Ascorbic Acid and Thermal

Abstract This study aimed to prepare reduced graphene oxide (RGO) with high electrical conductivity by changing the reduction sequences with environmentally friendly L-ascorbic acid and H 2 at moderate temperature. Graphene oxide (GO) was prepared by the modified Hummers method using graphite. The characteristic peak at about 2 θ :10° was observed in the XRD pattern, and the oxygen-containing functional groups determined by FTIR analyses indicate the successful preparation of graphene oxide (GO) In order to investigate the removal of oxygen-containing functional groups from GO and the restoration of the graphene structure, XRD, ATR-FTIR, XPS, and Raman analysis were performed. Also, SEM images were taken to see the change in the morphology of the materials. Electrical conductivity measurements of prepared GO and RGO materials were performed using the four-point probe method. RGO-AA-T material, to which first chemical and then thermal reduction is applied, was found to have the highest electrical conductivity value of 1.97 × 10 4 Sm −1 with the highest ratio of C/O:15.5 among other RGOs. XRD and Raman analysis results showed that the initial application of chemical reduction allowed the formation of fewer graphene layers and denser sp 2 domains responsible for the highest electrical conductivity among other materials. The sequence of chemical and thermal treatment significantly enhances the electrical conductivity of RGO by effectively removing oxygen functional groups, maximizing the restoration of sp 2 domains, and preserving structure. These results indicate that the chemical and thermal reduction sequence is very important in improving electrical conductivity. The chemical and thermal reduction applied in this study is a very promising method, and ten times higher electrical conductivity can be achieved compared to the literature.