Preparation of graphene with few defects using expanded graphite and rose bengal

Abstract

We report an easy exfoliation technique using expanded graphite and rose bengal that requires shorter sonication time compared to that of currently reported methods in order to produce an aqueous graphene dispersion and high-quality graphene sheets with few defects. This is a simple method for graphene preparation using expanded graphite and rose bengal (RB) with amphiphilic properties as a surfactant in a short reaction time. RB with a hydrophilic carboxyl group and a hydrophobic aromatic group helps to separate the expanded graphite (EG) layers and prevents reformation of the exfoliated graphene layersvia electrostatic repulsion. The obtained graphene flakes showed oxygenated sp³carbon on the sheet edge and consisted mostly of mono- and few-layer graphene with lateral dimensions of a few hundred nanometres. This method facilitates graphene preparation for various applications.