Nanocomposite films of nitrogen-doped carbon nanotubes decorated with copper nanoparticles

Nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were grown by means of chemical vapor deposition on either a platinum plate electrode (Pt) or a silicon/silicon oxide substrate ejected with gold/palladium (Si/SiO2/Au/Pd). The nanocomposite films Pt/N-MWCNTs and Si/SiO2/Au/Pd/N-MWCNTs were electrochemically decorated with copper nanoparticles (CuNPs). The electrochemical responses of fabricated nanocomposite films toward ferrocyanide/ferricyanide, [Fe(CN)6]3−/4− redox system were investigated in aqueous potassium chloride solutions by means of cyclic voltammetry and electrochemical impedance spectroscopy techniques. The findings demonstrate that the electrochemical performance of unmodified bare Pt electrode enhances progressively with the growth of N-MWCNTs on its surface and their decoration with CuNPs. This observation exhibits the excessive influence of the electrocatalytic properties of carbon nanotubes on the electrochemical performance of the Pt electrode. Nevertheless, nanocomposite film consisting of N-MWCNTs grown on bare Si/SiO2 substrate demonstrates obviously faster electron-transfer kinetics between electrode and analyte as well as greater sensitivity (lower limit of detection) toward [Fe(CN)6]3−/4− compared to Pt/N-MWCNTs/CuNPs. However, the growth of N-MWCNTs onto Si/SiO2 ejected with Au/Pd and decorated with CuNPs appears to have a significant negative impact on electrochemical performance of this particular composite film toward [Fe(CN)6]3−/4−.