| The electrocatalytic oxidation of organic molecules provides a source for the direct conversion of chemical energy to electrical energy. In order to be able to rationally design more active catalysts for this process, a sound understanding of the electrochemical reaction mechanism is required. Direct current electrochemical techniques have already shed significant light on the reaction for several systems. However, much remains unknown. This work applies the alternating current technique of impedance spectroscopy to several organic molecule-catalyst systems to determine what new information can be gained from this technique. The systems studied include (1) the electro-oxidation of methanol on polished polycrystalline platinum, (2) the electro-oxidation of methanol on platinum-ruthenium oxide, and (3) the electro-oxidation of formic acid on polished polycrystalline platinum.; The impedance spectroscopy of the electro-oxidation of methanol on polished polycrystalline platinum detected an adsorbed reaction intermediate and indicated potential dependence of the reaction mechanism, perhaps due to different co-adsorbed oxygen containing species. The time dependence of the impedance spectra illuminated the effect of the coverage of the adsorbed intermediate on the reaction. |
