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Effect of Chloride Oxidation on Local Electric Fields in Microelectrochemical Systems
Author(s) -
Davies Collin D.,
Johnson Sarah E.,
Crooks Richard M.
Publication year - 2019
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201901402
Subject(s) - electrochemistry , potential gradient , anode , chloride , ionic bonding , electric field , chemical physics , electrical resistivity and conductivity , conductivity , electrochemical potential , electric potential , chemistry , inorganic chemistry , ion , analytical chemistry (journal) , electrode , chemical engineering , environmental chemistry , physics , voltage , organic chemistry , quantum mechanics , engineering
We recently reported that electrochemical oxidation of Cl − to neutral Cl 2 decreases solution conductivity, thereby yielding a local electric field gradient. Here, we report detailed experimental results and simulations indicating that the situation is more complex than we originally thought. The key new findings are twofold. First, once generated, Cl 2 rapidly reacts with water to form ionic species that increase, rather than decrease, solution conductivity near the anode. Second, the electrochemical potential gradient measured in the vicinity of the anode during Cl − oxidation is dominated by differences in the chemical potential, rather than the electrical potential, of the solution. These findings clarify the electrochemical and chemical processes previously reported to enable desalination via faradaic Cl − oxidation.