Charge Transfer between Electroactive Species Immobilized on Carbon Surfaces by Aryl Diazonium Reduction. SECM Investigations

Abstract

Electron transfers in modified polyaryl multilayers containing redox active molecules (ferrocenyl moieties) have been investigated by scanning electrochemical microscopy (SECM) in feedback mode. The modified surfaces were prepared by the electro-reduction of aryl diazonium salts that provides anchoring layers for the immobilization of the electroactive groups. Two types of anchoring films were prepared, the first with aminophenyl and the second with phenylcarboxylic acid groups, allowing us to vary the oxidation level of the electroactive film. Determination of the apparent electron transfer rates between the modified surface and a series of redox mediators displaying increasing standard potentials permits the analysis of different processes involved in the charge transfer, namely, the permeation of the organic molecules (the mediator) and the conduction mechanism. In addition to the first oxidation of the immobilized molecules by the mediator at the solution−film interface, the global oxidation kinetics ...

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Identifiers

DOI

10.1021/JP911550J

Journal

The Journal of Physical Chemistry C

Year

2010