Preparation of polypyrrole-coated platinum modified electrode in chloroform in the presence of various supporting electrolytes and its use for the catalytic oxidation of hydroquinone in aqueous and chloroform solutions

Polypyrrole (PPy)-coated platinum modified electrode was prepared electrochemically in chloroform in the presence of tetrabutylammonium perchlorate, tosylate, tetrafluoroborate, periodate, and hydrogen sulphate. Evidence in favour of the occurrence of a redox reaction at the film/solution interface was given by ferrocene oxidation. The electrocatalytic effect of the PPy-coated electrode was revealed by oxidation of hydroquinone on it in water and chloroform. The influence of dopant anion, method of electrosynthesis and operation temperature were demonstrated. The calculated heterogeneous electron transfer rate constant (k(o)) at the PPy-modified Pt electrode at 25 degrees C was 1.4 x 10(-3) cm/sec which is 1000-fold greater than the value (< 10(-6) cm/sec) reported for bare electrode.