On the Determination of the Diffusion Coefficients of Electrons and of Potassium Ions in Copper(II) Hexacyanoferrate(II) Composite Electrodes

Autor:	Retter U, Lohse H, Siegler K, Heike Kahlert, Fritz Scholz
Rok vydání:	1998
Předmět:	Chemistry Inorganic chemistry Analytical chemistry chemistry.chemical_element Electrolyte Copper Surfaces Coatings and Films Dielectric spectroscopy Ion Electron transfer Warburg coefficient Materials Chemistry Physical and Theoretical Chemistry Nyquist plot Cyclic voltammetry
Zdroj:	The Journal of Physical Chemistry B. 102:8757-8765
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp981623q
Popis:	Composite electrodes of graphite, paraffin, and copper(II) hexacyanoferrate(II) (Cu hcf) were studied by cyclic voltammetry (0.05−1000 mV s-1) and electrochemical impedance spectroscopy (10 Hz to 1 MHz). Cyclic voltammetric measurements were also performed with copper(II) hexacyanoferrate(II) which was mechanically immobilized on a paraffin impregnated graphite electrode (PIGE). The Nyquist plots which were obtained from impedance measurements could be modeled with an adsorption process in series to the charge transfer of K+ ions between the electrolyte solution and the Cu hcf, the diffusion of K+ ions in the Cu hcf, and the conduction of electrons in the Cu hcf. The charge transfer and the diffusion of K+ ions obeys the Randles mechanism. The charge transfer resistance as well as the Warburg coefficient exhibit a minimum at the formal potential. Both effects could be explained theoretically on the basis of the potential dependence of the oxidized and reduced forms of Cu hcf. The electron transfer from th...
Databáze:	OpenAIRE
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