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Title: 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 (X z1 1 and X z2 2) plus one or more non-electroactive species (X z3 3,X z4 4...X zjmax jmax) where X zj j is the j th species with charge z j and concentration; c j. 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.: Σ jmax j=1[X zj j]=Σ jmax j=1 c j = S P 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:
;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
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:
Journal Article: 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. doi: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. doi: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}
}

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