Preparation and characterization of graphene nanosheets from graphite flakes through assisted intercalation-expansion using a microwave oven

Carbon-based structures have attracted attention due to their unique properties, combining excellent chemical, thermal mechanical, and electrical features. The use of microwave irradiation has been used to produce graphene materials and the identification of optimum synthesis parameters is crucial for the production of high-quality carbon structures. Herein, we describe a detailed temperature study for the production of expanded graphite nanosheets (GNs) via intercalation of sulfuric and nitric acids, followed by a rapid and energy-efficient process of microwave-assisted expansion and exfoliation. The results demonstrate that the proposed methodology was efficient in producing high-quality GNs with a size of approximately 1 nm. The temperature investigation revealed that heat treatment of 800 °C was the best, resulting in a high-quality material, achieving maximum expansion with the lowest weight loss related to thermal degradation. Thus, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests confirmed good electrochemical features of the sample produced at a temperature of 800 °C.