Abstract: Polypyrrole (PPy) films were synthesized by potentiolstatic method froma para-toluenesulfonic sodium (p-TSNa) solution on stainless steel. Cyclic voltammetry of PPy-modified electrodes in the wide potential range from -1.6 to 0.8 V was conducted in H2SO4, Na2SO4, and NaOH solutions, respectively. The results showed that cyclic voltammogramin H2SO4 solution was featured by H+ insertion during reduction process and H+ expulsion during oxidation process. A unique peak associated to H+ reduction was first discovered. In Na2SO4 and NaOH solutions, cyclic voltammograms are featured by Na+ insertion during reduction process and Na+ expulsion during oxidation process. The data of FT-IR absorption spectra demonstrated that NaOH treatment had made extensive structure degradation, but Na2SO4 and H2SO4 treatments had not made conjugated structure changes on PPy films.

Key words: Polypyrrole, Redox behavior, Electrolyte solutions, FT-IR