Synthesis and Characterization of Reduced Graphene Oxide from Indigenous Coal: A Non-Burning Solution

Abstract

Abstract: A great deal of research has been made into producing graphene or graphene oxide by utilizing graphite as a starting material. An alternate method of producing graphene is using low-grade coal as a starting material. Due to the abundance of coal in Pakistan and increased environmental concern from Government bodies and environmental agencies alike, increased awareness is being made to move over to non-burning solutions to fossil fuels. Experiments were performed on two ranks of coal in parallel; lignite and sub-bituminous. Coal was pretreated first to remove the undesired impurities, which could hinder the graphene synthesis later on. Acid washing with multiple waters was done, followed by carbonization in the furnace. After the pretreatment, the Hummers method was chosen as a chemical process for synthesizing graphene. It is a less complex method, can be easily performed with available resources, and is comparatively cheaper and environmentally friendly. The resulting sample was tested with SEM and EDS, and graphene oxide was confirmed. It was followed by a water-based reduction method to produce reduced graphene oxide from graphene oxide. This modified hydrothermal method was chosen for its eco-friendliness. The final sample was dried and tested with XRD, SEM, FTIR, and RAMAN to authenticate the type of graphene produced. Graphene has remarkable properties, including very high tensile modulus, extremely high thermal conductivity, and charge carrier mobility exceeding 200,000 cm²V^-1s^-1. Such properties are reason enough to explore low cost, environment friendly, and scalable means of graphene production. Potential graphene applications in various medical, chemical and industrial processes are enhanced or enabled by using new graphene materials.

Keywords: Coal, Graphene graphite, Hummers method, Hydrothermal method, Water-based reduction method.