Electrochemical behavior of Naphthol green B doped in polypyrrole film and its application for electrocatalytic oxidation of ascorbic acid

The polypyrrole doped with Naphthol green B (NGB/PPy) was synthesized by potentiostatic method at a platinum electrode. Electrochemical behavior of the NGB redox system in polypyrrole was studied by cyclic voltammetric method. This incorporated NGB was a good mediator for electrocatalysis of ascorbic acid (AA) and oxidation overpotential of AA was significantly reduced for about 320 mV compared with that obtained at bare Pt electrode. Amounts of rate constant of catalytic process, diffusion coefficient of AA in solution were calculated by choronoamperometric method and rotating disk electrode (RDE) voltammetry. In addition, this modified electrode exhibits high electrode stability for a long-term use. The dependence of response currents on the concentration of AA was examined and was linear in the range of 0.24-25 mM of AA. (C) 2006 Elsevier B.V. All rights reserved.