Study of technical parameters to prepare graphene dispersions by liquid phase exfoliation

Abstract:

Graphene a two-dimensional honeycomb structure has attracted huge attention due to its unique physical and chemical properties. Since its single layer isolation in 2004 [1], several approaches of graphene production have been proposed; as example bottom up and top down approaches. Particularly, top down approaches are most practical routes to obtain graphene due to the starting material employed, is natural graphite. Within those approaches, the liquid phase exfoliation of graphite [2, 3], either aqueous solutions or organic solvents, is a lowcost and scalable process. However, a standardized liquid phase exfoliation is not reported yet, owing to the various technical parameters involved, such as: initial graphite concentration, liquid medium, sonication time, centrifugation time and centrifugation rotor speed. To mitigate this necessity, we report a detailed study of the crucial role of each one, to produce high-quality well-dispersed graphene in organic solvents. Dimethylformamide and ethanol are the organic solvents selected to produce graphene from natural graphite flakes. The research is focused on a step-by-step UV-vis analysis (of the technical parameters) up to obtain high graphene concentrations in a reduced sonication time. To determinate a possible functionalization on graphene surface or graphene edges, IR analysis is carried out. 360 samples are analysed. The results are compared with previous works, and demonstrate that is viable to produce graphene in a short sonication time (5 hours) at concentrations up to 60 um/ml. This report pretends to be a guide line for large scale graphene production.

Año de publicación:

Keywords:

Fuente:

google