Potentiostatic-Potentiodynamic Reduction Synthesis of Anthraquinone Functionalized Graphene for Oxygen Reduction in Alkaline Medium

Through direct electrochemical potentiostatic-potentiodynamic reduction of the starting materials of graphene oxide (GO) and Fast Red Al Salt, the anthraquinone functionalized graphene nanocomposite was developed as a highly efficient electrocatalyst for oxygen reduction reaction (ORR) in alkaline conditions. Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy characterizations revealed that the most of oxygen- containing functional groups on GO were removed after electroreduction. The electrocatalytic ORR have systematically investigated by cyclic voltammetry, rotating disk electrode and rotating ring-disk electrode techniques. Results show that the anthraquinone covalently functionalized graphene afforded much greater electrocatalytic activity towards ORR in 0.1 M KOH than the sole graphene and anthraquinone covalently bonded glass carbon materials. At anthraquinone/graphene modified electrode, two reduction processes both attributed to 2e– reduction are recorded for ORR with HO-2 as intermediate. The presence of graphene nanosheets not only results in larger peak current and shifts the onset potential of ORR in the positive direction, but also leads to further reduction of partial HO-2 to OH– in the more negative potential region.