Electrochemical behavior of reduced graphene oxide and multi-walled carbon nanotubes composites for catechol and dopamine oxidation

Glassy carbon electrodes were modified by drop casting carbon nanomaterials, graphene oxide, GO, and multi-walled carbon nanotubes, MWCNTs, alone, mixed together (Composite) or in the form of bi-layers. The reduction of GO was carried out by means of a green approach using cyclic voltammetry (CV). Two model compounds, catechol and dopamine, which can be considered representative of the polyphenols class, were taken into account to determine the modifying system giving the highest oxidation current. Furthermore, the fouling effects of the electrode surface were also taken into account. The electrochemically active areas of the tested configurations were estimated by two approaches, to highlight the various phenomena that may affect the redox processes of the two analytes at the different chemically modified electrodes (CMEs). All the CMEs were characterized by SEM, FT-IR and UV–vis spectroscopies. In addition, zeta potential and heterogeneous electron transfer constant were determined. The most performing configuration was found to be the Composite, as it is the best compromise in terms of sensitivity and resistance to fouling.