Improved Electrochemical Preparation of Nano Porous-Graphene Oxide Edge Like Electrode for Cerium/Vanadium Redox Flow Batteries

A nano porous-graphene oxide edge like (NP-GOel) electrode is presented as an electrochemical active material for Ce(IV)/Ce(III) redox couples for Ce-V redox flow batteries. The medium used to prepare NP-GOel electrode was 2 M NH3 + 2% 2 M H2SO4 + 1% triton-100. The morphology and electrochemical properties of NP-GOel electrode were investigated by atomic force microscopy analysis, X-ray photoelectron spectroscopy, and cyclic voltammetry. Surface characterization results showed that that NP-GOel electrode possesses nanopores containing hydroxyl (R-OH) and epoxy (C-O-C) groups. This increase of nano pores containing oxygen functional groups provided excellent electrocatalytic activity towards Ce(IV)/Ce(III) redox couples, whereas normally activated and prepared in 2 M NH3 medium graphite showed sluggish quasi-reversible electron transfer activity towards Ce(IV)/Ce(III), suggesting that the Ce(IV)/Ce(III) redox reaction depends strongly on oxygen-containing groups generated on the surface of graphite and nano pores. When NP-GOel electrodes were modified with Nafion, electrode stability markedly increased with no change in electrode morphology. The electrochemically prepared NP-GOel shows promise for Cerium redox properties in Ce-V redox flow battery applications.