Abstract
Quantitative studies of electron transfer processes at electrode/electrolyte interfaces, originally developed for homogeneous liquid mercury or metallic electrodes, are difficult to adapt to the spatially heterogeneous nanostructured electrode materials that are now commonly used in modern electrochemistry. In this study, the impact of surface heterogeneity on Fourier-transformed alternating current voltammetry (FTACV) has been investigated theoretically under the simplest possible conditions where no overlap of diffusion layers occurs and where numerical simulations based on a 1D diffusion model are sufficient to describe the mass transport problem. Experimental data that meet these requirements can be obtained with the aqueous [Ru(NH3)6]3+/2+ redox process at a dual-electrode system comprised of electrically coupled but well-separated glassy carbon (GC) and boron-doped diamond (BDD) electrodes. Simulated and experimental FTACV data obtained with this electrode configuration, and where distinctly different heterogeneous charge transfer rate constants (k0 values) apply at the individual GC and BDD electrode surfaces, are in excellent agreement. Principally, because of the far greater dependence of the AC current magnitude on k0, it is straightforward with the FTACV method to resolve electrochemical heterogeneities that are ∼1-2 orders of magnitude apart, as applies in the [Ru(NH3)6]3+/2+ dual-electrode configuration experiments, without prior knowledge of the individual kinetic parameters (k0 1 and k0 2) or the electrode size ratio (θ1:θ2). In direct current voltammetry, a difference in k0 of >3 orders of magnitude is required to make this distinction.
| Original language | English |
|---|---|
| Pages (from-to) | 2830-2837 |
| Number of pages | 8 |
| Journal | Analytical Chemistry |
| Volume | 89 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 7 Mar 2017 |
Cite this
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Probing Electrode Heterogeneity Using Fourier-Transformed Alternating Current Voltammetry : Application to a Dual-Electrode Configuration. / Tan, Sze Yin; Unwin, Patrick Robert; Macpherson, Julie V; Zhang, Jie; Bond, Alan M.
In: Analytical Chemistry, Vol. 89, No. 5, 07.03.2017, p. 2830-2837.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Probing Electrode Heterogeneity Using Fourier-Transformed Alternating Current Voltammetry
T2 - Application to a Dual-Electrode Configuration
AU - Tan, Sze Yin
AU - Unwin, Patrick Robert
AU - Macpherson, Julie V
AU - Zhang, Jie
AU - Bond, Alan M.
PY - 2017/3/7
Y1 - 2017/3/7
N2 - Quantitative studies of electron transfer processes at electrode/electrolyte interfaces, originally developed for homogeneous liquid mercury or metallic electrodes, are difficult to adapt to the spatially heterogeneous nanostructured electrode materials that are now commonly used in modern electrochemistry. In this study, the impact of surface heterogeneity on Fourier-transformed alternating current voltammetry (FTACV) has been investigated theoretically under the simplest possible conditions where no overlap of diffusion layers occurs and where numerical simulations based on a 1D diffusion model are sufficient to describe the mass transport problem. Experimental data that meet these requirements can be obtained with the aqueous [Ru(NH3)6]3+/2+ redox process at a dual-electrode system comprised of electrically coupled but well-separated glassy carbon (GC) and boron-doped diamond (BDD) electrodes. Simulated and experimental FTACV data obtained with this electrode configuration, and where distinctly different heterogeneous charge transfer rate constants (k0 values) apply at the individual GC and BDD electrode surfaces, are in excellent agreement. Principally, because of the far greater dependence of the AC current magnitude on k0, it is straightforward with the FTACV method to resolve electrochemical heterogeneities that are ∼1-2 orders of magnitude apart, as applies in the [Ru(NH3)6]3+/2+ dual-electrode configuration experiments, without prior knowledge of the individual kinetic parameters (k0 1 and k0 2) or the electrode size ratio (θ1:θ2). In direct current voltammetry, a difference in k0 of >3 orders of magnitude is required to make this distinction.
AB - Quantitative studies of electron transfer processes at electrode/electrolyte interfaces, originally developed for homogeneous liquid mercury or metallic electrodes, are difficult to adapt to the spatially heterogeneous nanostructured electrode materials that are now commonly used in modern electrochemistry. In this study, the impact of surface heterogeneity on Fourier-transformed alternating current voltammetry (FTACV) has been investigated theoretically under the simplest possible conditions where no overlap of diffusion layers occurs and where numerical simulations based on a 1D diffusion model are sufficient to describe the mass transport problem. Experimental data that meet these requirements can be obtained with the aqueous [Ru(NH3)6]3+/2+ redox process at a dual-electrode system comprised of electrically coupled but well-separated glassy carbon (GC) and boron-doped diamond (BDD) electrodes. Simulated and experimental FTACV data obtained with this electrode configuration, and where distinctly different heterogeneous charge transfer rate constants (k0 values) apply at the individual GC and BDD electrode surfaces, are in excellent agreement. Principally, because of the far greater dependence of the AC current magnitude on k0, it is straightforward with the FTACV method to resolve electrochemical heterogeneities that are ∼1-2 orders of magnitude apart, as applies in the [Ru(NH3)6]3+/2+ dual-electrode configuration experiments, without prior knowledge of the individual kinetic parameters (k0 1 and k0 2) or the electrode size ratio (θ1:θ2). In direct current voltammetry, a difference in k0 of >3 orders of magnitude is required to make this distinction.
UR - http://www.scopus.com/inward/record.url?scp=85018260474&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.6b03924
DO - 10.1021/acs.analchem.6b03924
M3 - Article
VL - 89
SP - 2830
EP - 2837
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 5
ER -