Electron Transfer Reactions of Catechols at Ultrasmall Carbon Ring Electrodes

Uitrasmall carbon ring electrodes exhibit charge-selective enhancement of oxidation rates for a series of catechols following anodic electrochemical treatment. Voltammetry is more Nernstlan for cationic catechois and less Nernstian for anionic catechois after identical oxidative cycling of the electrode. This behavior is not observed for voltammetry obtained at disk-shaped carbon fiber electrodes. Double layer effects do not appear to be the dominant mechanism responsible for charge-selective electron transfer at carbon ring electrodes. The unique voltammetry for catechols at carbon ring electrodes suggests that the carbon formed by the pyrolysis step contains charge-selective sites that affect the electron transfer process. These sites may involve selective catechol adsorption on the electrode prior to electron transfer.