A comparative study of the anion transfer kinetics across the water/nitrobenzene interface by means of electrochemical impedance and square-wave voltammetry at thin organic film-modified electrode - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Langmuir Année : 2006

A comparative study of the anion transfer kinetics across the water/nitrobenzene interface by means of electrochemical impedance and square-wave voltammetry at thin organic film-modified electrode

Résumé

The kinetics of the transfer of a series of hydrophilic monovalent anions across the water/nitrobenzene (W/NB) interface has been studied by means of thin organic film-modified electrodes in combination with electrochemical impedance spectroscopy and square-wave voltammetry. The studied ions are Cl-, Br-, I-, ClO4 -, NO3 -, SCN-, and CH3COO-. The electrode assembly comprises a graphite electrode (GE) covered with a thin NB film containing a neutral strongly hydrophobic redox probe (decamethylferrocene or lutetium bis(tetra-tert-butylphthalocyaninato)) and an organic supporting electrolyte. The modified electrode is immersed in an aqueous solution containing a supporting electrolyte and transferring ions, and used in a conventional three-electrode configuration. Upon oxidation of the redox probe, the overall electrochemical process proceeds as an electron-ion charge-transfer reaction coupling the electron transfer at the GE/NB interface and compensates ion transfer across the W/NB interface. The rate of the ion transfer across the W/NB interface is the limiting step in the kinetics of the overall coupled electron-ion transfer reaction. Moreover, the transferring ion that is initially present in the aqueous phase only at a concentration lower than the redox probe, controls the mass transfer regime in the overall reaction. A rate equation describing the kinetics of the ion transfer that is valid for the conditions at thin organic film-modified electrodes is derived. Kinetic data measured with two electrochemical techniques are in very good agreement.

Dates et versions

hal-00457274 , version 1 (17-02-2010)

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Rubin Gulaboski, Valentin Mirceski, Carlos M. Pereira, M. Natalia D. S. Cordeiro, A. Fernando Silva, et al.. A comparative study of the anion transfer kinetics across the water/nitrobenzene interface by means of electrochemical impedance and square-wave voltammetry at thin organic film-modified electrode. Langmuir, 2006, 22, pp.3404-3412. ⟨10.1021/la052565k⟩. ⟨hal-00457274⟩
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