title: Diffuse Layer Effect on Electron-Transfer Kinetics Measured by Scanning Electrochemical Microscopy (SECM).
abstract: Recent theoretical and experimental studies revealed strong effects of the electrical double layer (EDL) on mass transfer at nanometer-sized electrodes and in electrochemical nanogaps. Although the EDL effect is much stronger in weakly supported media, it can significantly influence the kinetics of electron-transfer processes involving multicharged ionic redox species, even at high concentrations of supporting electrolyte. We measured the kinetics of Fe(CN)64-oxidation in 1 M KCl solution at the Pt nanoelectrode used as a tip in the scanning electrochemical microscope. The apparent standard rate constant values extracted from tip voltammograms without double-layer correction increased markedly with the decreasing separation distance between the tip and substrate electrodes. The same steady-state voltammograms were fitted to the theory including the EDL effect and yielded the rate constant essentially independent of the separation distance.
authors.affiliation: Department of Chemistry and Biochemistry, Queens College , Flushing, New York 11367, United States.
authors.forename: Je Hyun
authors.initials: JH
authors.lastname: Bae
authors.affiliation: Department of Chemistry and Biochemistry, Queens College , Flushing, New York 11367, United States.|The Graduate Center of CUNY , New York, New York 10016, United States.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Chemistry and Biochemistry, Queens College , Flushing, New York 11367, United States.|The Graduate Center of CUNY , New York, New York 10016, United States.
authors.forename: Michael V
authors.identifier: http://orcid.org/0000-0002-3424-5810
authors.initials: MV
authors.lastname: Mirkin