Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 8387-8393 |
| Number of pages | 7 |
| Journal | Analytical Chemistry |
| Volume | 87 |
| Issue number | 16 |
| DOIs | |
| Publication status | Published - 2015 |
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Determination of fast electrode kinetics facilitated by use of an internal reference. / Bano, Kiran; Bond, Alan Maxwell; Zhang, Jie.
In: Analytical Chemistry, Vol. 87, No. 16, 2015, p. 8387-8393.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Determination of fast electrode kinetics facilitated by use of an internal reference
AU - Bano, Kiran
AU - Bond, Alan Maxwell
AU - Zhang, Jie
PY - 2015
Y1 - 2015
N2 - The concept of using an internal reversible reference process as a calibration in the determination of fast electrode kinetics has been developed and applied with the technique of Fourier transformed large amplitude ac voltammetry to minimize the influence of errors arising from uncertainties in parameters such as electrode area (A), concentration (C), diffusion coefficient (D), and uncompensated resistance (Ru). Since kinetic parameters (electron transfer rate constant, k0, and electron transfer coefficient, α) are irrelevant in the voltammetric characterization of a reversible reaction, parameters such as A, C, D, and Ru can be calibrated using the reversible process prior to quantification of the electrode kinetics associated with the fast quasi-reversible process. If required, new values of parameters derived from the calibration exercise can be used for the final determination of k0 and α associated with the process of interest through theory-experimental comparison exercises. Reference to the reversible process is of greatest significance in diminishing the potentially large impact of systematic errors on the measurement of electrode kinetics near the reversible limit. Application of this method is demonstrated with respect to the oxidation of tetrathiafulvalene (TTF), where the TTF0/• process is used as a reversible internal reference for the measurement of the quasi-reversible kinetics of the TTF•/2+ process. The more generalized concept is demonstrated by use of the Fc0/+ (Fc = ferrocene) reversible process as an internal reference for measurement of the kinetics of the Cc+/0 (Cc+ = cobaltocenium) process. Via the internal reversible reference approach, a k0 value of 0.55 cm s-1 was obtained for the TTF•/2+ process at a glassy carbon electrode and 2.7 cm s-1 for the Cc+/0 one at a carbon fiber microelectrode in acetonitrile (0.1 M Bu4NPF6).
AB - The concept of using an internal reversible reference process as a calibration in the determination of fast electrode kinetics has been developed and applied with the technique of Fourier transformed large amplitude ac voltammetry to minimize the influence of errors arising from uncertainties in parameters such as electrode area (A), concentration (C), diffusion coefficient (D), and uncompensated resistance (Ru). Since kinetic parameters (electron transfer rate constant, k0, and electron transfer coefficient, α) are irrelevant in the voltammetric characterization of a reversible reaction, parameters such as A, C, D, and Ru can be calibrated using the reversible process prior to quantification of the electrode kinetics associated with the fast quasi-reversible process. If required, new values of parameters derived from the calibration exercise can be used for the final determination of k0 and α associated with the process of interest through theory-experimental comparison exercises. Reference to the reversible process is of greatest significance in diminishing the potentially large impact of systematic errors on the measurement of electrode kinetics near the reversible limit. Application of this method is demonstrated with respect to the oxidation of tetrathiafulvalene (TTF), where the TTF0/• process is used as a reversible internal reference for the measurement of the quasi-reversible kinetics of the TTF•/2+ process. The more generalized concept is demonstrated by use of the Fc0/+ (Fc = ferrocene) reversible process as an internal reference for measurement of the kinetics of the Cc+/0 (Cc+ = cobaltocenium) process. Via the internal reversible reference approach, a k0 value of 0.55 cm s-1 was obtained for the TTF•/2+ process at a glassy carbon electrode and 2.7 cm s-1 for the Cc+/0 one at a carbon fiber microelectrode in acetonitrile (0.1 M Bu4NPF6).
UR - http://pubs.acs.org.ezproxy.lib.monash.edu.au/doi/pdf/10.1021/acs.analchem.5b01667
U2 - 10.1021/acs.analchem.5b01667
DO - 10.1021/acs.analchem.5b01667
M3 - Article
VL - 87
SP - 8387
EP - 8393
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 16
ER -