Electrochemical exfoliation of a graphite electrode in 1-ethyl-3-methylimidazolium chloride-[EMIM]+Cl--AlCl3ionic liquid and its electrocatalytic application

Abstract

The electrochemical exfoliation of graphite using 1-ethyl-3-methylimidazolium chloride-[EMIM]Cl-AlCl3 ionic liquid (IL) has been anticipated to be an environmentally benign and economically viable graphene production technique based on the intercalation of AlCl4- ions into a graphite anode in an IL mixture. An equimolar mixture of the two solids AlCl3- and EMIMCl- becomes a liquid at room temperature via the acid-base reaction to form AlCl4- and EMIM+ ions. This liquid is not only an electrolyte, but also a source of electroactive species for intercalation into graphite. The crystallographic properties of graphite and physicochemical properties of the IL enable better intercalation of AlCl4- (2.95 Å) into the graphite layer (lattice distance 3.3 Å). The results clearly demonstrate that graphene is produced within the graphite anode in AlCl3-EMIM+Cl-. The IL is significantly important in terms of its cost efficiency, wide electrochemical window, and high exfoliation performance for the production of graphene. The as-prepared few-layer graphene was drop-casted on a pre-polished glassy carbon electrode (GCE), followed by the electrodeposition of Pt dendritic nanoparticles, for application in the electrooxidation of glucose.