Oxidation of a PPy‐modified tantalum electrode

A tantalum electrode on which polypyrrole (PPy) had been previously formed by electropolymerization was galvanostatically electrolyzed in an aqueous solution of 0.01 wt% phosphoric acid. This process contains the irreversible oxidation of a PPy film, the decomposition of solvent, and the formation of Ta₂O₅ by the reaction of OH⁻ coming through the PPy film, with Ta electrodes. A three layer‐structure (PPy/Ta₂O₅/Ta) was confirmed by electron spectroscopy for chemical analysis (ESCA). A PPy film containing CIO₄⁻ as dopant [PPy(CIO₄⁻)] was significantly deteriorated in comparison with PPy(TsO⁻) at the electrolysis. Therefore, the (PPy(TsO⁻)/Ta₂O₅/Ta) system showed better electrical characteristics as a capacitor than the (PPy(CIO₄⁻)/Ta₂O₅/Ta) system showed better electrical characteristics as a capacitor than the (PPy(ClO₄⁻)/Ta₂O₅/Ta) system.