Electrochemical impedance spectroscopic investigation of CO2 reduction on polyaniline in methanol

The ac response of polyaniline thin films on platinum electrodes was measured at different dc potentials during the CO2 reduction in methanol/LiClO4 electrolyte with a small amount of 0.5 M H2SO4. The complex capacitance curves were simulated and the data obtained were used to calculate kinetic parameters, based on the assumption that the thermodynamic potential E0 is in the region of -0.2--0.1 V versus saturated calomel electrode (SCE). With E0=-0.2 V versus SCE and β=0.6, a j0 value of ca. 10-4 A cm-2 was found for the electroreduction of CO2 on the polyaniline electrode