Preparation of Poly-N-Methylpyrrole Coated Platinum Modified Electrode in Chloroform in the Presence of Various Supporting Electrolytes and Its Use for the Catalytic Oxidation of Ascorbic Acid and Hydroquinone

The electrochemical preparation of poly-N-methylpyrrole (PMPy) coated platinum electrode in chloroform in the presence of tetrabutylammonium Perchlorate, hexafluorophosphate, hydrogensulphate, Periodate and Iodide as supporting electrolytes was performed. The influence of electrosynthesis method, dopant anion type and operation temperature on electrochemical behavior of polymer were demonstrated. The electrocatalytic effect of the PMPy-coated electrode revealed by its oxidation of ascorbic acid and hydroquinone in water. The electrochemical data show the occurrence of a redox reaction at the film/solution interface. Results in comparison to the literature show that the electrocatalytic effect of PMPy prepared in chloroform is greater than the polypyrrole prepared in this solvent and also PMPy prepared in acetonitrile has greater electrocatalytic effect than PMPy prepared in chloroform. The calculated heterogeneous electron transfer rate constant (K°) at the PMPy-modified Pt electrode at 25 °C was 8´10-4 cms-1 which is 800-fold greater than the value (<10-6 cms-1) reported for bare Pt electrode.