Autoclave-mediated reduction of graphene oxide for enhanced conductive films

Abstract

A highly efficient and environmentally friendly method for producing high-quality reduced graphene oxide (rGO) films is explored. It consists of a scalable autoclave process devoid of hazardous reductants. In detail, the reduction of four distinct graphene oxide materials, whose O/C ratio varied from 0.28 to 0.58, through an autoclave-mediated hydrothermal process at 200 °C and 12 bars pressure is carried out. This employs overheated steam as a heat carrier, without any additional solvents or reducing agents. Upon mild annealing (80 °C), the final rGO films result being robust, self-supporting, and electrically conductive. This study investigates the impact of both the initial GO’s oxidation degree and the volume distribution on the efficacy of the hydrothermal process in synthesizing rGO systems. Furthermore, a comparison between films, created through both hydrothermal autoclave-mediated and thermal oven-mediated methods, is conducted, by assessing their electrical, morphological, chemical, and structural properties. Films produced via the autoclave method display notably improved electrical surface resistivity (3.34·102 Ω/sq) compared to the traditional thermal treatments (6.71·105 Ω/sq). These promising results emphasize the potential of this eco-friendly route as a foundation for scalable and sustainable fabrication of valuable graphene-based conductive materials.