Rapid Production of Thermally Exfoliated Graphene with a Large Specific Surface Area by Introducing a Spray Predrying Process

Thermal exfoliation of graphite oxide (GTO) is a rapid and efficient method to obtain thermally exfoliated graphene (TEG) on a large scale. Generally, the effect of the thermal exfoliation process is studied to obtain a high specific surface area (SSA), whereas the importance of the predrying process is rarely discussed. In the present work, the influence of spray-assisted predrying on the final exfoliation of GTO was investigated. It was found that the introduction of spray drying did not change the basic units of the thermally exfoliated products comprised of six to eight layers of porous structures. However, it contributed to the formation of loose and more disordered structures, highly susceptible to the destruction caused by the gas generated during thermal exfoliation. Consequently, a higher SSA of 870 ± 74 m2·g-1 with more pores among all the structural units could be obtained. This work helps to understand the influence of spray drying on the TEG, and conveniently associates the predrying and thermal exfoliation processes to achieve a continuous operation.