Ionic liquid crystal – mediated preparation of reduced graphene oxide under microwave irradiation

Abstract

Synthesis of pure graphene is still a highly challenging task and one of the common methods employed is, the oxidation of graphite to obtain graphene oxide (GO) followed by the reduction of oxygen functionalities in GO to yield reduced graphene oxide (RGO). By utilizing the dielectric properties of ionic liquid crystals (ILCs) to facilitate rapid microwave heating, we describe the preparation of reduced graphene oxide, starting from graphite. Besides, assisting the rapid microwave heating, the order and the anisotropic properties of the mesophase exhibited by ILCs are expected to influence the formation of the nanomaterial. The commercially obtained graphite flakes were oxidized to GO using modified Hummer’s method. The GO was reduced under the microwave (700 W, 23 s) in the presence of two structurally different ILCs to obtain RGO. The reduction of GO was also carried out in the presence of an ionic liquid (IL) and the absence of ILC and IL. The RGO was thoroughly characterized using standard analytical techniques. A higher percentage of reduction in the oxygen content was observed for RGO samples which were reduced in the presence of ILCs in comparison to RGO samples reduced in the presence of IL and the absence of ILC/IL.