Ultrasonication assisted mild solvothermal synthesis and morphology study of few-layered graphene by colloidal suspensions of pristine graphene oxide

In the present work, a simple and systematic approach for the reduction of graphene oxide (GO), that converts to chemically modified graphene at low temperature (T=200 degrees C) using ultrasonication assisted mild solvothermal method without the use of any surfactants/stabilizers has been employed. Graphene Oxide sheets are reduced in polar and non-polar organic liquid media under ultrasonication and thermal process conditions, which aids in active high yield chemically modified few layers graphene sheets with tunable C/O ratios dependent on the boiling point of the solvent. The reaction time, temperature, auto generated pressure in the reaction vessel and the reducing power of the solvents influenced the extent of reduction of graphene oxide sheets to modified graphene sheets. This study examined the dispersion behavior of graphene oxide in a polar solvent and non-polar, as well as the differences in the behavior in various solvents related to the solubility parameter. The chemically modified graphene produces a flexible morphology with a large surface area and micro porous distribution resulting in sheets/flakes like materials generated by very simple ultrasonication and thermal exfoliation of the reduced graphene oxide sheets in a wide variety of organic solvent. (C) 2016 Elsevier Inc. All rights reserved.