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Degoulange D, Pandya R, Deschamps M, Skiba D, Gallant B, Gigan S, de Aguiar H, Grimaud A. Direct imaging of micrometer-thick interfaces in salt-salt aqueous biphasic systems. Proc Natl Acad Sci U S A 2023; 120:e2220662120. [PMID: 37068232 PMCID: PMC10151592 DOI: 10.1073/pnas.2220662120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/26/2023] [Indexed: 04/19/2023] Open
Abstract
Unlike the interface between two immiscible electrolyte solutions (ITIES) formed between water and polar solvents, molecular understanding of the liquid-liquid interface formed for aqueous biphasic systems (ABSs) is relatively limited and mostly relies on surface tension measurements and thermodynamic models. Here, high-resolution Raman imaging is used to provide spatial and chemical resolution of the interface of lithium chloride - lithium bis(trifluoromethanesulfonyl)imide - water (LiCl-LiTFSI-water) and HCl-LiTFSI-water, prototypical salt-salt ABSs found in a range of electrochemical applications. The concentration profiles of both TFSI anions and water are found to be sigmoidal thus not showing any signs of a positive adsorption for both salts and solvent. More striking, however, is the length at which the concentration profiles extend, ranging from 11 to 2 µm with increasing concentrations, compared to a few nanometers for ITIES. We thus reveal that unlike ITIES, salt-salt ABSs do not have a molecularly sharp interface but rather form an interphase with a gradual change of environment from one phase to the other. This knowledge represents a major stepping-stone in the understanding of aqueous interfaces, key for mastering ion or electron transfer dynamics in a wide range of biological and technological settings including novel battery technologies such as membraneless redox flow and dual-ion batteries.
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Affiliation(s)
- Damien Degoulange
- Chimie du Solide et de l’Energie, UMR 8260, Collège de France,75231 Cedex 05Paris, France
- Sorbonne Université,75006Paris, France
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
| | - Raj Pandya
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
- Department of Physics, Cavendish Laboratory, University of Cambridge, CambridgeCB3 0HE, United Kingdom
| | - Michael Deschamps
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
- CNRS, Conditions Extrêmes et Matériaux : Haute Température et Irradiation, UPR3079, Université d'Orléans,45071Orléans, France
| | - Dhyllan A. Skiba
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Betar M. Gallant
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
| | - Hilton B. de Aguiar
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, Université PSL, CNRS, Sorbonne Université, Collège de France,75005Paris, France
| | - Alexis Grimaud
- Chimie du Solide et de l’Energie, UMR 8260, Collège de France,75231 Cedex 05Paris, France
- Sorbonne Université,75006Paris, France
- Réseau sur le Stockage Electrochimique de l’Energie, CNRS FR3459,80039Amiens Cedex, France
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA02467
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Papaderakis AA, Al Nasser HA, Chen JY, Juel A, Dryfe RA. Deciphering the mechanism of electrowetting on conductors with immiscible electrolytes. Electrochim Acta 2023. [DOI: 10.1016/j.electacta.2023.142342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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Liu C, Ma Y, Xu Z, You Y, Bai S, Nan J, Wang L. Galvani Potential-Dependent Single Collision/Fusion Impacts at Liquid/Liquid Interface: Faradic or Capacitive? J Phys Chem B 2022; 126:9705-9714. [PMID: 36356196 DOI: 10.1021/acs.jpcb.2c05741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A new subtype of nano-impacts by emulsion droplets via reorganization of the electric double layer (EDL) at the liquid/liquid interface (LLI) is reported. This subtype shows anodic, bipolar, and cathodic transient currents with a potential of zero charge (PZC) dependence, revealing the non-faradic characteristic of single fusion impacts. In addition, the absolute integrated mean charge is proportional to the Galvani potential at the ITIES, indicating that the EDL at the LLI may obey the discrete Helmholtz model. The exact PZC point is interpolated from the fitting curve, and the droplet size distribution is estimated from the integrated charge distribution. Moreover, the different values of Epzc between single fusion impacts of MgCl2 droplets and pure water droplets is due to the specific absorption between Mg2+ and antagonistic anion in the organic phase. The influence of the concentration of the supporting electrolyte is also investigated. The above work gives physicochemical insights into the EDL at the micropipette-supported LLI and provides potential application to measure micro/nanoscale heterogeneous media without catalytic, reactive, or charge-transfer activity via impact experiments at LLI.
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Affiliation(s)
- Cheng Liu
- School of Chemistry, South China Normal University, Guangzhou510006, China
| | - Yamin Ma
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou510641, China
| | - Zhidan Xu
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou510641, China
| | - Yongtao You
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou510641, China
| | - Silan Bai
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou510641, China
| | - Junmin Nan
- School of Chemistry, South China Normal University, Guangzhou510006, China
| | - Lishi Wang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou510641, China
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Jetmore HD, Anupriya ES, Cress TJ, Shen M. Interface between Two Immiscible Electrolyte Solutions Electrodes for Chemical Analysis. Anal Chem 2022; 94:16519-16527. [DOI: 10.1021/acs.analchem.2c01416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Henry David Jetmore
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
| | | | - Tanner Joe Cress
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
| | - Mei Shen
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
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Bhattacharyya D, Videla PE, Cattaneo M, Batista VS, Lian T, Kubiak CP. Vibrational Stark shift spectroscopy of catalysts under the influence of electric fields at electrode-solution interfaces. Chem Sci 2021; 12:10131-10149. [PMID: 34377403 PMCID: PMC8336477 DOI: 10.1039/d1sc01876k] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
External control of chemical processes is a subject of widespread interest in chemical research, including control of electrocatalytic processes with significant promise in energy research. The electrochemical double-layer is the nanoscale region next to the electrode/electrolyte interface where chemical reactions typically occur. Understanding the effects of electric fields within the electrochemical double layer requires a combination of synthesis, electrochemistry, spectroscopy, and theory. In particular, vibrational sum frequency generation (VSFG) spectroscopy is a powerful technique to probe the response of molecular catalysts at the electrode interface under bias. Fundamental understanding can be obtained via synthetic tuning of the adsorbed molecular catalysts on the electrode surface and by combining experimental VSFG data with theoretical modelling of the Stark shift response. The resulting insights at the molecular level are particularly valuable for the development of new methodologies to control and characterize catalysts confined to electrode surfaces. This Perspective article is focused on how systematic modifications of molecules anchored to surfaces report information concerning the geometric, energetic, and electronic parameters of catalysts under bias attached to electrode surfaces. Heterogeneous electrocatalysis: characterization of interfacial electric field within the electrochemical double layer.![]()
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Affiliation(s)
- Dhritiman Bhattacharyya
- Department of Chemistry, Emory University 1515 Dickey Drive Northeast Atlanta Georgia 30322 USA
| | - Pablo E Videla
- Department of Chemistry and Energy Sciences Institute, Yale University 225 Prospect Street New Haven Connecticut 06520 USA
| | - Mauricio Cattaneo
- INQUINOA-UNT-CONICET, Facultad de Bioquímica, Química y Farmacia, Instituto de Química Física, Universidad Nacional de Tucumán Ayacucho 471 (4000) San Miguel de Tucumán Argentina
| | - Victor S Batista
- Department of Chemistry and Energy Sciences Institute, Yale University 225 Prospect Street New Haven Connecticut 06520 USA
| | - Tianquan Lian
- Department of Chemistry, Emory University 1515 Dickey Drive Northeast Atlanta Georgia 30322 USA
| | - Clifford P Kubiak
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, MC 0358 La Jolla California 92093 USA
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Gschwend GC, Girault HH. Discrete Helmholtz model: a single layer of correlated counter-ions. Metal oxides and silica interfaces, ion-exchange and biological membranes. Chem Sci 2020; 11:10304-10312. [PMID: 34094294 PMCID: PMC8162434 DOI: 10.1039/d0sc03748f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/09/2020] [Indexed: 01/31/2023] Open
Abstract
The mechanism by which interfaces in solution can be polarised depends on the nature of the charge carriers. In the case of a conductor, the charge carriers are electrons and the polarisation is homogeneous in the plane of the electrode. In the case of an insulator covered by ionic moieties, the polarisation is inhomogeneous and discrete in the plane of the interface. Despite these fundamental differences, these systems are usually treated in the same theoretical framework that relies on the Poisson-Boltzmann equation for the solution side. In this perspective, we show that interfaces polarised by discrete charge distributions are rather ubiquitous and that their associated potential drop significantly differs from those of conductor-electrolyte interfaces. We show that these configurations, spanning liquid-liquid interfaces, charged silica-water interfaces, metal oxide interfaces, supercapacitors, ion-exchange membranes and even biological membranes can be uniformly treated under a common "Discrete Helmholtz" model where the discrete charges are compensated by a single layer of correlated counter-ions, thereby generating a sharp potential drop at the interface.
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Affiliation(s)
- Grégoire C Gschwend
- Laboratoire d'Electrochimie Physique et Analytique (LEPA), École Polytechnique Fédérale de Lausanne (EPFL) Rue de l'Industrie 17 CH-1951 Sion Switzerland
| | - Hubert H Girault
- Laboratoire d'Electrochimie Physique et Analytique (LEPA), École Polytechnique Fédérale de Lausanne (EPFL) Rue de l'Industrie 17 CH-1951 Sion Switzerland
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