On the nature of redox processes in the cyclic voltammetry of polypyrrole nitrate in aqueous solutions

Abstract

The counter-anion doping states and redox processes of polypyrrole nitrate (PPy(NO3-)) were studied by elemental analysis, cyclic voltammetry and spectroelectrochemical measurements. Two counter-anion doping sites, the positively charged conjugated chain of PPy (site 1) and the protonated pyrrole (py) unit (site 2), were distinguished. It was found that the counter-anions in site 2 are removed with the deprotonation of the py unit in a neutral or basic aqueous solution, while those in site 1 are exchanged with OH- in a basic solution. Two redox processes of PPy(NO3-) in aqueous solutions, corresponding to the two doping sites, were observed. The mechanisms of the redox processes in acidic, neutral and basic solutions are discussed. © 1993.