Electrochemical Characterization of Binderless, Recompressed Exfoliated Graphite Electrodes: Electron-Transfer Kinetics and Diffusion Characteristics

Ramesh, P and Sampath, S (2003) Electrochemical Characterization of Binderless, Recompressed Exfoliated Graphite Electrodes: Electron-Transfer Kinetics and Diffusion Characteristics. In: Analytical Chemistry, 75 (24). pp. 6949-6957.

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Abstract

Exfoliated graphite (EG) is prepared by the thermal exfoliation of graphite intercalation compounds at different temperatures. Surface and bulk physicochemical properties of EG are followed by spectroscopic and analytical methods and are observed to be a function of exfoliation temperature. EG particles can be recompressed without any binder and used as surface-renewable electrodes. Surface preparation is accomplished by either polishing or roughening the electrode surface using emery sheets. Effects of exfoliation temperature and the surface preparation on the electron-transfer kinetics and on the diffusion characteristics have been followed by electrochemical methods using several benchmark redox systems. It is found that the electron-transfer kinetics and the diffusion of $K_4[Fe(CN)_6]$ are affected by the nature of the EG surface while that of iron(II)$(1,10-phenanthroline)_3$ and cobalt(II)$(1,10-phenanthroline)_3$ are not affected by the surface preparation. The redox systems are classified into different groups according to their kinetic sensitivity. Diffusion of electroactive species toward the EG electrodes is found to nonlinear. Current-time plots suggest that the recompressed EG electrodes can be modeled as fractals.

Item Type:	Journal Article
Publication:	Analytical Chemistry
Publisher:	American Chemical Society
Additional Information:	The Copyright belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	26 Apr 2006
Last Modified:	19 Sep 2010 04:26
URI:	http://eprints.iisc.ac.in/id/eprint/6490

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