Production of few-layer graphene by wet media milling using organic solvents and different types of graphite

One of the main challenges in the exploitation of nanomaterials is their production at low cost. Mechanical milling is an alternative for the production of nanomaterials, such as graphene. In this work we have studied the effect of different solvents (methanol, ethanol, acetone, hexane, toluene and xylene) on the production of graphene by attrition milling of graphite. Among the solvents tested, methanol showed to be able to produce graphene sheets more efficiently. Computer modeling suggests that although methanol and acetone have a weaker interaction with graphene (3.95 and 7.41 kcal/mol, respectively) compared to xylene (12.73 kcal/mol), they have a higher Gibbs free energy (6.46, 3.81 and 0.33 kcal/mol for methanol, acetone and xylene, respectively), suggesting a higher mobility on its surface, thus facilitating the exfoliation of graphene. The production of graphene was corroborated by Raman spectroscopy and transmission electron microscopy, showing to be a few layers graphene (<5 layers), approximately 1–6 μm in length, with a high degree of graphitization. Additionally, we also show that through this route is feasible to produce a few-layer graphene using synthetic and amorphous graphite as more economical alternatives.