| This dissertation is presented in three parts: The first part describes the investigation of platinum modified polypyrrole nanocomposite electrodes. The catalytic activity of the modified polypyrrole (ppy) electrode towards the dioxygen reduction and the hydrogen oxidation reaction was tested in 0.05 M H{dollar}rmsb3POsb4{dollar} and 0.5 M H{dollar}rmsb2SOsb4{dollar} respectively, with the polymer film thickness and platinum catalyst loading as variables. In both cases an increase in the reaction cross-section with the polymer film thickness was noted. The hydrodynamic voltammetry data were analyzed and rate limiting mechanisms for charge transfer were identified.; The second part describes the development of a novel electrochemical flow system for the study of the dynamics and quantitative aspects of counterion transport at chemically modified electrodes. The flow cell includes two working electrodes: a "generator" electrode, comprising a glassy carbon disk chemically modified with a polypyrrole/Fe(CN){dollar}sb6sp{lcub}4-{rcub}{dollar} (ppy/FCN) layer, and a "collector" electrode further downstream. With ppy/FCN as a demonstration model, we show that the efficiency of Fe(CN){dollar}sb6sp{lcub}-4{rcub}{dollar} ejection from the ppy film is sensitive to the film thickness and the reduction potential. New information on the mechanistic aspects of the growth of ppy/FCN films are also presented using chronopotentiometry and electrochemical quartz microgravimetry data.; Finally, a new form of chemical degradation of the electrosynthesized ppy is reported. A variety of techniques, including electrochemistry, spectroscopy and quartz crystal microgravimetry were used to investigate the basis of the phenomenon. An electrolysis product, hypochlorite, was found to be the cause of the chemical degradation of the ppy film. |
