Electrochemical Study of Graphene and its Oxidized Form

Abstract

Two types of graphene samples were electrochemically studied namely the as-synthesized graphene sample and the oxidized graphene sample. The electrochemical response was evaluated using Fe(CN)63-/4-, and  Ru(NH3)62+/3+. The comparison was made based on the apparent heterogeneous electron transfer rate constant, and charge transfer resistance. Both graphene samples demonstrate extremely low background current which is the excellent criterion in designing biosensor. The introduction of higher carbon-oxygen functionalities on oxidized graphene exhibits lower electron transfer rate constant as compared to the as-synthesized graphene. Furthermore, oxidized graphene sample shows the excellent properties in resisting biofouling of -nicotinamide adenine dinucleotide (NADH) and achieves detection limit of 10 nM. It shows that the oxygen functionalities on graphene surface renders it to be an excellent candidate for sensitive biosensor.