Electrocatalytic reduction of oxygen at poly(4-amino-3-hydroxynaphtalene sulfonic acid), poly(2aminobenzoic acid) and poly(8-aminonaphtalene -2-sulfonic acid) -modified glassy carbon electrodes
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Date
2009-06
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Addis Ababa Universty
Abstract
The electrochemical behavior and the electrocatalytic activity of polymer modified glassy carbon electrodes for oxygen reduction reaction (ORR) were examined using cyclic and rotating disk voltammetric techniques. Glassy carbon electrodes were modified by electropolymerization of 4-amino-3-hydroxynaphtalene sulfonic acid (AHNSA), 2-aminobenzoic acid (ABA) and 8-aminonaphtalene-2-sulfonic acid (ANSA). Use of a rotating disk electrode allowed to separate the different contributions in the overall reaction: diffusion of molecular oxygen in the electrolyte solution (0.5M HSO24), diffusion inside the film, adsorption process and electron transfer. Koutecky- Levich analysis made possible to evaluate the kinetic parameters (total number of exchanged electron, limiting current density, Tafel slope and exchange current density ). The electrocatalytic behavior of 4-amino-3-hydroxynaphtalene sulfonic acid (AHNSA) , 2-aminobenzoic acid (ABA) and 8-aminonaphtalene-2-sulfonic acid (ANSA) modified glassy carbon electrodes were compared based on both the exchange current density (io) and the overpotential values at a common current density.
Keywods: Electrocatalysis, Electropolymerization, ORR, Overpotential, Tafel slope
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Electrocatalysis, Electropolymerization, ORR, Overpotential, Tafel slope