title: Scanning Electrochemical Microscopy of Metal/Metal Oxide Electrodes. Analysis of Spatially Localized Electron-Transfer Reactions during Oxide Growth.
abstract: Scanning electrochemical microscopy (SECM) has been used to study the oxidation of iodide at Ta electrodes covered by a thin (∼2.5 nm) film of Ta(2)O(5). SECM images of surface activity reveal that the voltammetric response of a macroscopic Ta electrode comprises the individual responses of a large number of microscopic sites, each with its own unique electrochemical behavior. Oxide film growth and metal dissolution occur simultaneously with iodide oxidation, resulting in a complex voltammetric response. The component of the voltammetric current due to iodide oxidation can be separated from the total current by SECM analysis. The growth of nanometer-thick oxide films can also be studied using SECM by monitoring the rate at which iodide is oxidized at the electrode surface.
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City, Utah 84112.
authors.forename: S B
authors.initials: SB
authors.lastname: Basame
authors.forename: H S
authors.initials: HS
authors.lastname: White