Electrochemistry at liquid/liquid interfaces: methodology and potential applications

doi:10.1016/S0013-4686(00)00343-1

Electrochimica Acta

Volume 45, Issues 15–16, 3 May 2000, Pages 2647-2662

https://doi.org/10.1016/S0013-4686(00)00343-1 Get rights and content

Abstract

Electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) gains more and more interest due to its wide range of applications. The present review encompasses the various domains of charge transfer reactions in biphasic systems, with some emphasis on certain studies that marked the advances of electrochemistry at ITIES and that, in a noticeable manner, have been presented in large majority at the ISE meetings during the last two decades. These studies, as well as some subjects in which our recent research interest is concerned, are used here to describe the fundamental aspects of charge transfer reactions at liquid/liquid interfaces and to outline their various applications. This overview presents the methodologies offered by the ITIES in the fields of amperometric sensors, solvent extraction, pharmacokinetics, thermo-electricity and solar energy conversion, and the accent is put on the perspectives of their potential development in the coming years.

Introduction

Electrochemistry at the interface between two immiscible electrolyte solutions is a rather new topic of electrochemistry, which has been present at every meeting of the International Society of Electrochemistry (ISE) for the last decade.

The first experiments in the field were reported at the end of the last century, but it was only in the 1970s that the subject enjoyed a new era of growth. The pioneer of this renewed interest in the field was Claude Gavach in France who started to apply electrochemical methods to study ion transfer reactions [1], [2], [3], [4].

Then, the relay was taken by the Heyrovsky Institute in Prague under the influence of Professor Koryta [5], [6], [7], [8], [9], [10], [11] former president of the ISE (1985–1986). It was around this time that the acronym ITIES (interface between two immiscible electrolyte solutions) was coined and has remained ever since. When the ISE meeting was held in Prague in 1990, a plenary lecture entitled: ‘Electrochemical Processes at the Interface between Two Immiscible Solutions of Electrolytes’ was given by Professor Senda who has been the pioneer of the field in Japan. This plenary lecture was followed by the first ISE micro symposium on Immiscible Electrolytes with Professor T. Kakiuchi as Chairman.

In this review article, we shall first recall the fundamental aspects of charge transfer reactions at the ITIES and we shall present our views on some potential applications.

Section snippets

Interfacial structure

The interface between two solvents is by nature a molecular interface with its own dynamics. It is characterised by the fact that it is difficult to define an interfacial structure or thickness as the time scale becomes a parameter of the definition. Is the interface sharp or diffuse? The answer to this question is timescale dependent.

From an experimental viewpoint, capillary wave measurements by X-ray or neutron scattering [12], [13], [14], [15], [16], [17] did not provide yet a proper

Amperometric sensors and ionodes

Ion selective electrodes rely on ion or facilitated ion transfer reactions to establish a potential difference that depends on the concentration of the target ions. Potentiometric sensors depend on thermodynamic equilibria and can therefore be used to measure activities. Amperometric sensors on the other hand depend on diffusion controlled mass transfer and are therefore proportional to the concentrations. Considering that both ion transfer and assisted ion transfer reactions are reversible,

Conclusion

If the field of electrochemistry of liquid/liquid interfaces has progressed rapidly over the last couple of decades, many issues are still a matter of debate.

From a theoretical viewpoint, the key aspects of potential distribution remain the major challenge. Without a good modelling of the potential distribution, in the absence or in the presence of specific adsorption, it will be difficult to progress in the kinetics analysis of charge transfer reactions. However, considering that most transfer

Acknowledgements

The authors want to express their gratitude to Professor Z. Samec from the Academy of Sciences of the Czech Republic and to Professor T. Kakiuchi from the Kyoto University of Japan for fruitful discussions and helpful comments on this paper.

References (185)

C. Gavach et al.
Electrochim. Acta
(1974)
C. Gavach et al.
Bioelectrochem. Bioenerg.
(1974)
C. Gavach et al.
J. Electroanal. Chem.
(1974)
Z. Samec et al.
J. Electroanal. Chem.
(1977)
J. Koryta
Electrochim. Acta
(1979)
J. Koryta et al.
Bioelectrochem. Bioenerg.
(1980)
J. Koryta
Ion-Sel. Electrode Rev.
(1983)
J. Koryta
Anal. Chim. Acta
(1986)
J. Koryta
Electrochim. Acta
(1988)
J. Als-Nielsen
J. Phys. A
(1986)

M. Gros et al.

J. Electroanal. Chem.

(1978)

Z. Samec et al.

J. Electroanal. Chem.

(1981)

W. Schmickler

J. Electroanal. Chem.

(1999)

Z. Samec et al.

J. Electroanal. Chem.

(1985)

T. Wandlowski et al.

Electrochim. Acta

(1995)

V. Marecek et al.

Adv. Colloid Interface Sci.

(1988)

M. Senda et al.

Electrochim. Acta

(1991)

T. Kakiuchi et al.

J. Electroanal. Chem.

(1992)

Y. Shao et al.

J. Electroanal. Chem.

(1991)

D. Homolka et al.

J. Electroanal. Chem.

(1982)

T. Kakiuchi et al.

J. Electroanal. Chem.

(1991)

F. Reymond et al.

J. Electroanal. Chem.

(1998)

F. Reymond et al.

J. Electroanal. Chem.

(1998)

H.H. Girault

J. Electroanal. Chem.

(1995)

B.B. Smith et al.

Chem. Phys.

(1996)

Z. Samec

J. Electroanal. Chem.

(1979)

W. Schmickler

J. Electroanal. Chem.

(1997)

Z. Ding et al.

J. Electroanal. Chem.

(1998)

V. Marecek et al.

J. Electroanal. Chem.

(1987)

V. Marecek et al.

J. Electroanal. Chem.

(1988)

V. Marecek et al.

J. Electroanal. Chem.

(1989)

E. Wang et al.

Trends Anal. Chem.

(1988)

J. Koryta et al.

J. Electroanal. Chem.

(1976)

J. Koryta et al.

J. Electroanal. Chem.

(1977)

V. Marecek et al.

Anal. Chim. Acta

(1983)

V. Marecek et al.

Anal. Chim. Acta

(1986)

H.J. Lee et al.

J. Electroanal. Chem.

(1998)

H.J. Lee et al.

J. Electroanal. Chem.

(1997)

F. Silva et al.

Electrochim. Acta

(1997)

H.J. Lee et al.

Electrochem. Comm.

(1999)

J. Koryta

Electrochim. Acta

(1987)

O. Shirai et al.

J. Electroanal. Chem.

(1995)

R.D. Armstrong et al.

Electrochim. Acta

(1992)

V. Horvath et al.

Anal. Chim. Acta

(1993)

C.J. Bender et al.

Anal. Chim. Acta

(1987)

J. Kutnik et al.

Bioelectrochem. Bioenerg.

(1986)

T. Kakiuchi

Electrochim. Acta

(1998)

C. Gavach

Experientia

(1971)

D. Homolka et al.

Anal. Chem.

(1980)

D. Baeglehole

Experimental studies of liquid interfaces

Cited by (269)

Interfacial polycondensation of polyamides studied at the electrified liquid-liquid interface
2023, Electrochimica Acta
In this work, we present the possibility to electrochemically assist and study the interfacial polycondensation derived from the reactions between 1,6-diaminohexane or p-phenylenediamine (used as the diamine initially present in the aqueous phase) and acyl chlorides in a form of 1,3,5-benzenetricarbonyl trichloride, terephthaloyl chloride or adipoyl chloride (present in the organic phase – 1,2-dichloroethane solution). Polyamides are synthesized at the polarized liquid – liquid interfaces (or the interface between two immiscible electrolyte solutions – ITIES) as a consequence of the transfer of partly protonated diamines from the aqueous to the organic phase. In this respect, we have defined the aqueous phase pH assuring the availability of amine groups (-NH₂) for the reaction with the acyl chloride and protonated amine groups (-NH₃⁺) defining the electrochemical interfacial activity of chosen compounds. The possibility to electrochemically assist the interfacial formation of polyamides was first tested using the macroscopic ITIES. Formed polyamides were collected and analysed using scanning electron microscopy, energy dispersive x-ray spectroscopy and Raman spectroscopy. Next, we have employed the microscopic ITIES (microITIES) based system formed using fused silica microcapillaries. Cyclic voltammetry was employed for the polyamide modified microITIES assessment (evolution of molecular sieving properties using a model ion - tetramethylammonium cation).
Electrochemical properties of cyclen and cyclam macrocycles bearing ferrocenyl pendants and their transition metal complexes
2023, Journal of Electroanalytical Chemistry
The ligands [R-Fc(cyclen)], [Fc(cyclen)₂], [Fc(cyclam)₂], [Fc₂(cyclen)] and [Fc₄(cyclen)] (R = –H or –CH₂OH; Fc = ferrocene; cyclen = 1,4,7,10-tetraazacyclododecane; cyclam = 1,4,8,11-tetraazacyclotetradecane) and their respective Cu²⁺, Co²⁺, Cd²⁺, Zn²⁺, and Ni²⁺ metal complexes have been synthesised and electrochemically characterised. The voltammetry of the free ligands in a CH₂Cl₂/CH₃CN (1:4) solvent mixture containing [Bu₄N][PF₆] or [Bu₄N](B(C₆F₅)₄] as the supporting electrolyte yields two closely spaced oxidation processes. The first one is Fc based, and the other is related to the interaction of the Fc with the nitrogen component. Details of the mechanism were established by studying the oxidation of N,N-dimethylaminomethylferrocene by cyclic voltammetry and bulk electrolysis with product isolation. However, cyclic voltammetries exhibit a single Fc-based reversible oxidation process when the ligands form metal complexes with Cu²⁺, Co²⁺, Cd²⁺, Zn²⁺, or Ni²⁺. Upon metal ion binding, an important positive shift in the reversible midpoint potential, E_m, is observed. The magnitude of the shift in the E_m values follows the order [Fc(cyclen)₂] ≈ [Fc(cyclam)₂] ≫ [R-Fc(cyclen)] ≈ [Fc₂(cyclen)] > [Fc₄(cyclen)]. The ability of the ligands to work as electrochemical sensors for the mentioned cations is discussed.
An electrochemical perspective on the interfacial width between two immiscible liquid phases
2023, Current Opinion in Electrochemistry
Molecular dynamics simulations and vibrational sum-frequency spectroscopy are historically the main techniques applied to the description of the molecular structure and dynamics of the immiscible liquidǀliquid interface. A molecular sharpness is estimated for oilǀwater interfaces, with an interfacial width that extends from hundreds of Å to 1 nm. However, electrochemical studies have elucidated a deeper liquidǀliquid interface on the order of several micrometers. The breaking down of single-entity electrochemistry into simpler systems and the combination of high-resolution microscopies is confirming a larger extension of the interface. What can be the role of the electrochemist in clarifying this fundamental question? We try to give a suggestion at the end of a brief historical overview of the liquidǀliquid interface studies.
Nanoelectrodes for intracellular and intercellular electrochemical detection: Working principles, fabrication techniques and applications
2023, Journal of Electroanalytical Chemistry
Electrochemical nanoelectrodes are emerging as suitable probes in chemical and biochemical molecules detection inside single cells. In-situ measurements, faster detection time and cost effectiveness are just some of the advantages of such technology. With this approach, the investigation of metabolic and single cell mechanisms gives accurate and meticulous results. The precise and localized estimation of different analytes concentration allows to predict in advance the progression of a particular disease. In the first part of the review, the scenario related to nanoelectrochemistry applications for intracellular and intercellular sensing is reported together with an overview of the most interesting analytes for intra and intercellular detection; moreover, main nanoelectrodes fabrication processes and electrochemical techniques are discussed and compared. In the second part, different examples are reported according to the detection mechanism employed, focusing on electroactive material stability in biological systems and methods to improve their selectivity. A discussion about their different working principles and electrode architectures/functionalizations highlights the most relevant benefits and drawbacks of each one. Moreover, a schematic summary pointing out the principal results at the state of the art is reported.
Oxidized thin aluminum films used as the polarized liquid-liquid interface support for norcocaine detection
2022, Sensors and Actuators B: Chemical
In this work, the surface of thin (around 100 nm thick) porous aluminum film was thermally oxidized and used as the electrified liquid-liquid interface support. Constructed platforms provided quasi-sigmoidal voltammetric characteristic for the forward interfacial transport of all studied model ions (quaternary ammonium cations) typical for the microscopic liquid-liquid interfaces supported with pore(s) with a diameter exceeding the support thickness. Thin aluminum films before and after heat treatment were characterized using ion transfer voltammetry, scanning electron microscopy, optical profilometry and contact angle measurements. Finally, the utility of the constructed devices was verified during voltammetric norcocaine sensing in artificial and spiked real urine samples. Norcocaine gave a clear signal recorded within the available potential window and could be detected from the concentration equal to around 10 µM. The parameters such as limit of detection, limit of quantification, detection sensitivity, diffusion coefficient, and water/1,2–dichloroethane partition coefficient are also provided and tabulated.
Enhanced hydrogen evolution via in situ generated 2D black phosphorous nanocomposites at the liquid/liquid interfaces
2022, Applied Surface Science
The mimicry of bio-membrane with a liquid/liquid interface between two immiscible electrolyte solutions is intrinsically defect-free to study catalysis of energy conversion reactions i.e., CO₂ reduction, oxygen reduction, and hydrogen evolution. Herein, we report the in-situ generation of electrodeposited black phosphorous (BP) based nanocomposites at the liquid/liquid interface for the first time and their catalysis in hydrogen evolution reaction (HER). The catalytic HER activities of these catalysts have been investigated electrochemically and also chemically by two-phase reactions. The BP/MoS_x, BP/Cu, and BP/Pt nanocomposites were formed by reducing the catalyst precursors such as (NH₄)₂MoS₄, (NH₄)₂PtCl₄, and CuCl₂ salts, respectively on the BP nanosheets by decamethylferrocene (DMFc) electron donor during the catalytic HER. The electrodeposited nanocomposites were collected from the interface and characterized by using advanced analytical techniques. Among them, the BP/MoS_x nanocomposites showed the highest HER activity with a reaction rate constant of 0.202 min⁻¹ was about 230- and 7-times greater than the ones obtained by non-catalytic reaction and the free-MoS_x catalyst. Moreover, the nucleation of the catalysts and the HER mechanisms were also explained in detail. The BP/MoS_x also showed higher HER activity compared to that of carbon nanotubes CNTMoS_x and reduced graphene oxide rGOMoS_x nanocomposites.

View all citing articles on Scopus

View full text

Electrochemistry at liquid/liquid interfaces: methodology and potential applications

Abstract

Introduction

Section snippets

Interfacial structure

Amperometric sensors and ionodes

Conclusion

Acknowledgements

Electrochim. Acta

Bioelectrochem. Bioenerg.

J. Electroanal. Chem.

J. Electroanal. Chem.

Electrochim. Acta

Bioelectrochem. Bioenerg.

Ion-Sel. Electrode Rev.

Anal. Chim. Acta

Electrochim. Acta

J. Phys. A

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

Electrochim. Acta

Adv. Colloid Interface Sci.

Electrochim. Acta

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

Chem. Phys.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

Trends Anal. Chem.

J. Electroanal. Chem.

J. Electroanal. Chem.

Anal. Chim. Acta

Anal. Chim. Acta

J. Electroanal. Chem.

J. Electroanal. Chem.

Electrochim. Acta

Electrochem. Comm.

Electrochim. Acta

J. Electroanal. Chem.

Electrochim. Acta

Anal. Chim. Acta

Anal. Chim. Acta

Bioelectrochem. Bioenerg.

Electrochim. Acta

Experientia

Anal. Chem.

Experimental studies of liquid interfaces