Electrochemical Impedance Spectroscopic Study of Polyaniline on Platinum, Glassy Carbon and Carbon Fiber Microelectrodes

In this study, aniline (ANI) was electropolymerized on three different electrodes; platinum (Pt), glassy carbon (GC), and carbon fiber micro electrodes (CFME) in acid aqueous solution (0.5 M H2SO4) by cyclic voltammetry (CV). Electrode / PANI / electrolyte system was studied by electrochemical impedance spectroscopy (EIS). The results indicate the choice of electrode has a little effect on anodic (Ea) and cathodic peak potentials (Ec) during electropolymerization process. An equivalent electrical circuit (R(Q(R(C(R(C(RW))))(CR)) was proposed for PANI on three different electrodes. The highest low frequency capacitance (Csp=120 mF / cm2) was obtained for PANI / Pt electrode compared to PANI / CFME (239.1 μ F / cm2) and PANI / GC (38.9 μF / cm2) electrode. However, the highest double layer capacitance was obtained for PANI / CFME (Cdl = 190.9 mF / cm2) than Pt electrode (58.2 mF / cm2) and GC (24.3 mF / cm2).