Study of Ion Transfer Across the Liquid−Liquid Interface Coupled to Electrochemical Redox Reaction at the Pt Electrode with a Three-Electrode Potentiostat

Abstract

The ion transfer across the liquid−liquid interface coupled to electrochemical redox reaction at the Pt electrode was investigated simultaneously with a three-electrode potentiostat in combination with cyclic voltammetry. The approach involves using a small aqueous droplet containing a redox couple supported on a platinum electrode and immersed into an organic electrolyte solution. Both electron and ion transfer processes can be observed at separate interfaces for the first time. The effects of concentrations of the redox couple on ion transfer indicate that the overall electrochemical process, proceeding as a coupled electron−ion transfer reaction, is controlled by the electron transfer across the Pt/W interface and the electron-transfer reaction is the drive force of ion transfer across the L/L interface. In addition, for the first time, a new oscillation phenomenon has been observed directly, which is related to the L/L interface, to concentration of ferrocyanide and to potential scan range. The oscillation is caused by the formation of an ion pair at the interface between Fe(CN)6 4- in the aqueous phase and TAB+ in the DCE phase.

Investigation of the electrochemical processes related to IT coupling with ET by hydrophilic droplet electrodes

“…Lu et al have also investigated the effect of different redox concentrations but they only focused on oscillatory phenomena [44,45]. Until now, the effect of different concentrations of redox couple on coupled reactions has not been investigated systematically.…”

Ion Transport Traversing Bioinspired Ion Channels at Bionic Interface

“…Moreover, L/L interface is the simplest and most promising model for understanding charge-transfer process in biological systems. The advantages of this model include simple device and easy operation, as well as fast mass-transfer rate, negligibly small resistive potential drop, low double-layer charging current, and simple steady-state measurements by reducing the liquid/liquid interface to the nanometer range. , In nature, almost every life cycle involves the process of cross-channel ion transport. In general, it is more complex and more important for living organisms in regulating ion transport.…”

Melittin Adsorption and Lipid Monolayer Disruption at Liquid–Liquid Interfaces

“…Since then, phospholipid monolayers adsorbed at liquid–liquid interfaces formed between two immiscible electrolyte solutions (ITIES) have been used to mimic the behavior of lipid bio-membranes, especially to investigate the stability and ion permeability of the monolayers as a function of the well-defined interfacial potential difference. In parallel, less than two decades ago, the use of aqueous (organic) droplets supported on an electrode and immersed into an organic (aqueous) electrolyte solution to study electron transfer reactions coupled to ion transfer reactions was proposed . In these three-phase junctions (metal–water–oil), one of the interfaces is made not polarizable to study charge transfer reactions at the other interface.…”