Electrocatalytic Activity and Electrochemical Impedance Spectroscopy of Poly(Aniline-Co-Ortho-Phenylenediamine) Modified Electrode on Ascorbic Acid

摘要

The poly(aniline-co-ortho-phenylenediamine) modified composite graphite (poly(Ani-co-oPDA)/CG)) has shown excellent electrocatalytic response towards the oxidation of ascorbic acid (AA). The anodic peak potential (E_(pa)) of AA has shifted from +0.48 V (bare CG) to +0.17 V (poly(Ani-co-oPDA/CG)).the anodic peak currents (I_(pa)) are linearly dependent upon the square root of scan rate indicating a favourable diffusion controlled process. The electro oxidation of AA on poly(Ani-co-oPDA/CG is more feasible in acidic medium than in either neutral or alkaline medium. This is shown by negative shift of E_(pa). The charge transfer resistance (R_(ct)) at the poly(Ani-co-oPDA/ CG) shows that the rate of the electro oxidation of AA changes with electrode potential. The R_(ct) and diffusion process are dependant not only on applied potential and electrode material but also on the AA.