Effect of Chloride Oxidation on Local Electric Fields in Microelectrochemical Systems

Journal Article · 23 September 2019 · ChemElectroChem

DOI: https://doi.org/10.1002/celc.201901402 · OSTI ID:1565992

Davies, Collin D. ^[1]; Johnson, Sarah E. ^[1]; Crooks, Richard M.  ^[1]

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1. Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin, Texas 78712-1224 U.S.A.

Abstract 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.

• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-06ER15758
• OSTI ID: 1565992
• Journal Information: ChemElectroChem, Journal Name: ChemElectroChem Vol. 6 Journal Issue: 18; ISSN 2196-0216
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English