Electrochemical Oxidation of Phenol at Carbon Nanotube Electrode

The carbon nanotubes synthesized by hot-filament chemical vapor deposition were modified by concentrated nitric acid with a little surfactant. The electrochemical oxidation of phenol at the carbon nanotube electrode has been studied in phosphate buffer solution by cyclic voltammetry. The results showed that the direct electron transfer reactions on the carbon nanotube electrode surface could occur in the potential region of water stability, which resulted in the active groups on the carbon nanotubes due to the chemical modification. The well defined and reproductive oxidation peaks at 0.73 V vs. SCE, scan rate 50 mV/s-1 were clearly observed at the carbon nanotube electrode, which indicated that the electrode could avoid electrode fouling. The reaction process was controlled by diffusion process. The anodic peak current increased linearly with the concentration of phenol in the range of 1.0 x 10-5-1.0 x 10-4 mol/L-1 in cyclic voltammetric measurement. The electrochemical oxidation of phenol was also carried out on a fresh polished GC electrode for comparison, which did not have well defined oxidation peak and peak current decayed rapidly down with the every cycle. The mechanism of oxidation was discussed in details.