Abstract

Ali Parsa^* and Sara Amanzadeh-Salout

DOI : http://dx.doi.org/10.13005/ojc/320432

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. 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 (R_ct) at the poly(Ani–co–oPDA/CG) shows that the rate of the electro oxidation of AA changes with electrode potential.

Ascorbic acid; Electrochemical impedance spectroscopy; Electrocatalytic oxidation; Ortho–Phenylenediamine

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