Correlation between redox species adsorption and electron transfer kinetics of mildly oxidized graphene: A chronocoulometry and SECM study

The influence of redox species adsorption on the heterogeneous electron transfer (HET) rate of graphene, as well as the methodology for the rational design of intermolecular interactions to optimize the performance of graphene as an electrode modifier, are not completely understood. We investigate the influence of redox species adsorption on the HET rate of a mildly oxidized graphene-modified electrode by chronocoulometry (CC) and cyclic voltammetry (CV) combined with scanning electrochemical microscopy (SECM), using outer-sphere redox species FcCH₂OH^1+/0 and inner redox species Fe(CN)₆ ^4−/3–. The results demonstrate that adsorption of outer-sphere redox species on mildly oxidized graphene induces enhancement of HET, which bridges the differences regarding the reactivity of basal and edge plane sites of graphene in the recent literature.