Influence of the reduction strategy in the synthesis of reduced graphene oxide

Abstract

In this work, a comparative study of the different graphene oxide reduction strategies to produce reduced graphene oxide are discussed. Firstly, the optimization of the well-known oxidation route reported in literature (Improved Hummers Method) to obtain graphite oxide was carried out. Subsequently, different sets of reduced graphene oxide powders were synthesized through three different reduction routes: chemical, thermal and multiphase methods in order to obtain the most effective reduction strategy. Samples were analyzed by Raman spectroscopy, SEM, FTIR, elemental analysis, X-ray Diffraction and TGA. It was demonstrated that multiphase reduction method, e.g. combination of more than one reduction route, specifically, thermal and chemical ones, allowed to enhance the effectiveness for the removal of the oxygen functional groups. A mild thermal treatment followed by a chemical reduction of graphene oxide using ascorbic acid as reducing agent, showed that the 47% of oxygen functional groups was reduced. This manuscript demonstrates that the amount of oxygen functional groups in the reduced graphene oxide structure is highly dependent on the reduction strategy. These amount of oxygen functional groups could directly affect the use of reduced graphene oxide in the different potential applications proposed in bibliography.