Covalent double functionalization of graphene oxide for proton conductive and redox-active functions

Abstract

The covalent double functionalization of graphene oxide (GO) is an effective approach to tune the properties of graphene-like materials. The first step is the ring-opening reaction of epoxides by amines, followed by the second step consisting on the nucleophilic addition reaction of GO hydroxyl groups to an α,β-unsaturated carbonyl compound. The benefit of doubly functionalized GO is to possess different functions, confirmed by measuring proton conductivity and supercapacitor performance. The proton conductivity can be improved by introducing sulfonic acid and redox-active functional groups on GO, while the capacitance for supercapacitor can be increased by introducing two distinct redox-active molecules. The current study evidences that a double functionalization allow to design a multifunctional GO platform as an electrolyte membrane for fuel cells and/or an electrode material for supercapacitors.