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 Ta 2 O 5 by the reaction of OH − coming through the PPy film, with Ta electrodes. A three layer‐structure (PPy/Ta 2 O 5 /Ta) was confirmed by electron spectroscopy for chemical analysis (ESCA). A PPy film containing CIO 4 − as dopant [PPy(CIO 4 − )] was significantly deteriorated in comparison with PPy(TsO − ) at the electrolysis. Therefore, the (PPy(TsO − )/Ta 2 O 5 /Ta) system showed better electrical characteristics as a capacitor than the (PPy(CIO 4 − )/Ta 2 O 5 /Ta) system showed better electrical characteristics as a capacitor than the (PPy(ClO 4 − )/Ta 2 O 5 /Ta) system.