The Modified Liquid‐Liquid Interface: The Effect of an Interfacial Layer of MoS₂ on Ion Transfer

Abstract

MoS2 nanosheets have been assembled at the water|1,2‐dichlorobenzene (DCB) interface into uniform films, and the ion‐transfer properties investigated by voltammetry at the interface between immiscible electrolyte solutions. Remarkably, interfacial MoS2 films were found to enhance the simple and facilitated transfer of cationic species while restricting the transport of anionic species. The enhancement is attributed to a localised increase in the cationic concentration at the interface due to the adsorption onto the negatively charged surface of the exfoliated MoS2 nanosheets. Size‐selectivity for the cationic species was also recognized as a feature of such films. Characterisation of the interfacial film's structure revealed the inclusion of multiple emulsified droplets stabilised by MoS2, where the droplet number and size depend on the concentration of the MoS2 dispersion. Besides increasing the interfacial corrugation and area, the emulsified droplets are believed to influence the mass transport mechanism across the interface. Cyclic voltammetric measurements of saturated films suggested a capillary‐like structure of these films. While the capillaries/nanochannels allow them to have a degree of size‐selectivity that depends on the thickness/density of the film, they also affect the diffusion zones towards and away from the interface. Consequently, steady‐state conditions of mass transport similar to those found in solid‐state supported micro‐ITIES are observed in these nanofilms.

Hydrogen Evolution, Oxygen Evolution, and Oxygen Reduction at Polarizable Liquid|Liquid Interfaces

“…Hopefully, the concept of utilizing biphasic reaction within fuel cell/ electrolyzer for hydrogen peroxide generation [110] will be realized with heterogeneous catalyst assembled at the liquid j liquid interface. In this context, better understanding of ion transfer across liquid j liquid interface modified with nanoobject assembly [140,141] is desirable. So far, almost all studies of biphasic HER, OER and ORR focused on quiescent system with two bulk phases are in direct contact and interfacial area is restricted by the size and shape of the cell.…”

“…Hopefully, the concept of utilizing biphasic reaction within fuel cell/electrolyzer for hydrogen peroxide generation [110] will be realized with heterogeneous catalyst assembled at the liquid|liquid interface. In this context, better understanding of ion transfer across liquid|liquid interface modified with nanoobject assembly [140,141] is desirable.…”

Pickering emulsion-derived nano/microreactors for unconventional interfacial catalysis: state-of-the-art advances and perspectives in green reactions

“…The scientific community's main goal now is to increase the stability of O/W and W/O PEs by employing solid particles that can be used directly for biphasic catalysis. [135][136][137][138][139][140][141] Many possible organic and inorganic particles with fascinating characteristics remain unexplored. Owing to their advantages as inhibitors with high atomic efficiency, 2D compounds like tungsten di-selenide and molybdenum-disulfide could be suitable stabilizers for PEs.…”

Voltammetric Study of Lomefloxacin Transfer at the Interface between Two Immiscible Electrolyte Solutions: Ionic Partition, Photodegradation, and Sensing Applications

“…Electrochemical studies of the ion transfer process across a polarized interface between two immiscible electrolyte solutions (ITIES) are a useful platform for understanding the physical, thermodynamic, and pharmacokinetic properties of ionizable antibiotic drug molecules. [1][2][3][4][5][6][7][8][9][10][11] For example, Zanotto et al developed a procedure for understanding the first or pseudo-first order kinetic constant of ionizable tylosin A, an antibiotic drug, at an aqueous/1,2-dichloroethane (1,2-DCE) interface. [3] Puri et al studied the transfer kinetics of six different antibiotics, including nalidixic acid, difloxacin, flumequine, sulfadimethoxine, sulfamerazine, and sulfamethazine across a nanopipette-supported water/1,2-DCE interface.…”

“…Electrochemical studies of the ion transfer process across a polarized interface between two immiscible electrolyte solutions (ITIES) are a useful platform for understanding the physical, thermodynamic, and pharmacokinetic properties of ionizable antibiotic drug molecules [1–11] . For example, Zanotto et al.…”