Electrocatalytic activity and electrochemical impedance spectroscopy of poly(aniline-co-ortho-phenylenediamine) modified electrode on ascorbic acid

Abstract

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 (Epa) of AA has shifted from +0.48 V (bare CG) to +0.17 V (poly(Ani-co-oPDA/CG)). The anodic peak currents (Ipa) 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 Epa. The charge transfer resistance (Rct) at the poly(Ani-co-oPDA/CG) shows that the rate of the electro oxidation of AA changes with electrode potential. The Rct and diffusion process are dependant not only on applied potential and electrode material but also on the AA. (Graph Presented). The poly(aniline-co-ortho-phenylenediamine) modified composite graphite (CG) electrode has shown excellent electrocatalytic response towards the oxidation of ascorbic acid (AA). Charge transfer resistance (Rct) at the poly(Ani-co-oPDA/CG) shows that the rate of the electro oxidation of AA changes with electrode potential.