Single and double thermal reduction processes for synthesis reduced graphene oxide assisted by a muffle furnace: A facile robust synthesis and rapid approach to enhance electrical conductivity

Nowadays, with the rapid development of electronic devices, it is increasingly important to enhance the electrical conductivity of reduced graphene oxide (rGO). Thermal reduction (TR) temperature and time play the most crucial role as they control the electrical conductivity of rGO in terms of removal of oxygen-containing functional (OCF) groups. This work proposes a novel systematic approach for quick calibration of the OCF groups and lattice defects of GO to increase the conductivity by tuning the temperature and exposure time of the sample to the temperature. Single TR (STR) and double TR (DTR) processes were used in the current work, in which samples were exposed to temperatures of 500, 700, and 900 °C for 5 min. Further annealing took place for each sample at the same temperature with various reduction times. The results indicate that the DTR process improved the electrical conductivity of rGO samples. The highest enhancement of rGO500-5, rGO700-5, and rGO900-5 conductivities was 52.36%, 57.58%, and 231.81%, respectively. Consequently, this material can be used as a filler to get a well dispersed nanocomposite by accurate addition of rGO in a matrix, which enhances its electrical properties. Based on x-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and electrical analyses, the plausible STR and DTR mechanism of GO to rGO is effectively proposed.