Optimization of reduced graphene oxide yield using response surface methodology

Abstract

The efficient synthesis of reduced graphene oxide (RGO) by one-step chemical reduction of graphene oxide (GO) was carried out using sodium sulfate (Na2SO4) as a reducing agent. The aim of this study was to find the optimum conditions for the production of RGO as a function of reduction time, reduction temperature and GO:Na2SO4 weight ratio. The Box-Behnken design (BBD) method of the Response surface methodology (RSM) was used to optimize three variable factors (reduction temperature (25–95 °C), reduction time (1−12h), GO:Na2SO4 weight ratio ([1:1]-[1:20]) on the RGO yield. The optimum conditions obtained by the RSM method were given as a weight ratio of [1:10.5] GO:Na2SO4, a reduction temperature of 60 °C, and a reduction time of 6.5 h. The predicted optimum conditions obtained by RSM showed that the amount of RGO increased with the weight ratio of the GO:Na2SO4. The obtained RGO was characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV–Vis) spectroscopy to confirm that high quality RGO was synthesized with appropriate amount. XRD analysis suggested that the π-conjugated structure of RGO was significantly restored with the removal of oxygen functional groups. The RSM method can improve the experiment as a low cost method that can be used with a small number of experiments and experimental materials to give the highest yield of RGO.