Optimization of graphene oxide synthesis parameters for improving their after-reduction material performance in functional electrodes

Abstract

Optimization of the parameters of a modified Hummers' method for graphene oxide (GO) synthesis is conducted in this study. Focusing specifically on their applications for transparent electrodes and supercapacitor electrodes, the properties of the thin layers and electrodes prepared from GO and thermally reduced GO(RGO) were investigated using UV-visible spectroscopy, Hall measurements, atomic force microscopy, x-ray photoelectron spectroscopy, and cyclic voltammetry. The obtained results reveal that promoting the oxidation of graphite, either by increasing the acid reaction time or the oxidant dosage, improves the morphological and optoelectrical properties of the resulting graphene thin layers for transparent electrode applications. On the other hand, improving the synthesis parameters was not necessary for obtaining high-quality supercapacitor electrodes. Adopting thermal reduction conditions (involving thermal shocking) was as effective as using optimized synthetic conditions in increasing the gravimetric specific capacitance for the supercapacitor electrodes prepared using RGO.