Concentration and density changes at an electrode surface and the principle of unchanging total concentration
Abstract
In this study, the principle of unchanging total concentration as described by Oldham and Feldberg [J. Phys. Chem. B, 103, 1699 (1999)] is invoked to analyze systems comprising a redox pair (Xz11 and Xz22) plus one or more non-electroactive species (Xz33,Xz44...Xzjmaxjmax) where Xzjj is the jth species with charge zj and concentration; cj. The principle states that if the diffusion coefficients for all species are identical and mass transport is governed by the Nernst-Planck expression, the total concentration does not change during any electrochemical perturbation, i.e.: Σjmaxj=1[Xzjj]=Σjmaxj=1 cj = SP With this principle we deduce the electrochemically induced difference between the surface and bulk concentrations for each species. Those concentration differences are translated into density differences which are a function of the density of the solvent and of the concentration differences, molecular masses and the standard partial molar volumes of all species. Those density differences in turn can induce convection that will ultimately modify the observed current. However, we did not attempt to quantify details of the natural convection and current modification produced by those density differences.
- Authors:
-
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Publication Date:
- Research Org.:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- OSTI Identifier:
- 1240714
- Report Number(s):
- BNL-111892-2016-JA
Journal ID: ISSN 0013-4651; R&D Project: 2016-BNL-EE630EECA-Budg; KP1701000
- Grant/Contract Number:
- SC00112704
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of the Electrochemical Society
- Additional Journal Information:
- Journal Volume: 163; Journal Issue: 4; Journal ID: ISSN 0013-4651
- Publisher:
- The Electrochemical Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES; electrode surfaces
Citation Formats
Stephen W. Feldberg, and Lewis, Ernie R. Concentration and density changes at an electrode surface and the principle of unchanging total concentration. United States: N. p., 2016.
Web. doi:10.1149/2.0231604jes.
Stephen W. Feldberg, & Lewis, Ernie R. Concentration and density changes at an electrode surface and the principle of unchanging total concentration. United States. https://doi.org/10.1149/2.0231604jes
Stephen W. Feldberg, and Lewis, Ernie R. Wed .
"Concentration and density changes at an electrode surface and the principle of unchanging total concentration". United States. https://doi.org/10.1149/2.0231604jes. https://www.osti.gov/servlets/purl/1240714.
@article{osti_1240714,
title = {Concentration and density changes at an electrode surface and the principle of unchanging total concentration},
author = {Stephen W. Feldberg and Lewis, Ernie R.},
abstractNote = {In this study, the principle of unchanging total concentration as described by Oldham and Feldberg [J. Phys. Chem. B, 103, 1699 (1999)] is invoked to analyze systems comprising a redox pair (Xz11 and Xz22) plus one or more non-electroactive species (Xz33,Xz44...Xzjmaxjmax) where Xzjj is the jth species with charge zj and concentration; cj. The principle states that if the diffusion coefficients for all species are identical and mass transport is governed by the Nernst-Planck expression, the total concentration does not change during any electrochemical perturbation, i.e.: Σjmaxj=1[Xzjj]=Σjmaxj=1 cj = SP With this principle we deduce the electrochemically induced difference between the surface and bulk concentrations for each species. Those concentration differences are translated into density differences which are a function of the density of the solvent and of the concentration differences, molecular masses and the standard partial molar volumes of all species. Those density differences in turn can induce convection that will ultimately modify the observed current. However, we did not attempt to quantify details of the natural convection and current modification produced by those density differences.},
doi = {10.1149/2.0231604jes},
journal = {Journal of the Electrochemical Society},
number = 4,
volume = 163,
place = {United States},
year = {Wed Feb 17 00:00:00 EST 2016},
month = {Wed Feb 17 00:00:00 EST 2016}
}
Web of Science