Cyclic voltammetry of ion transfer across the polarized interface between the organic molten salt and the aqueous solution

Voltammetry of Ion Transfer across the Electrochemically Polarized Micro Liquid-Liquid Interface between Water and a Room-temperature Ionic Liquid, Tetrahexylammonium Bis(trifluoromethylsulfonyl)imide, Using a Glass Capillary Micropipette

“…The potential of the righthand-side terminal with respect to the left is hereafter denoted as E. The cell construction shown in Fig. 1 is basically the same as the one we reported previously, 17 except for the glass capillary, instead of an Ag/AgCl electrode, which was inserted in the RTIL phase. The interface between M and W1 is polarizable, while that at W2 and M is nonpolarized.…”

“…The relative magnitude of the hydrophobicity of THAC1C1N is thus similar to those of THAC2C2N, and also of NB, as we suggested previously. 17,20 Any comparison of the E1/2 values of the cations with those of the anions seems to be premature, as the difference between E1/2 and E 0 ′ due to the difference between the diffusion coefficients of the ions in THAC1C1N and W is opposite for the cations and anions, and the magnitude of the difference is presumably large, yet unknown. The fact that the E1/2 value of TPrA + is 0.02 V more positive than that of ClO4 -in Table 1 may be used to estimate the value of α in Eq.…”

“…[12][13][14] The interface between a RTIL and W may be either polarized or nonpolarized, depending on the solubility or hydrophobicity of the RTIL. [15][16][17][18] When the polarized potential window is wide enough, conventional voltammetric techniques can in principle be employed in studying the charge-transfer processes, 17,19,20 as is the case of conventional electrochemical systems composed of an electronic conductor in contact with an electrolyte solution. However, hydrophobic RTILs are generally much more viscous than conventional solvents; the viscosity is typically two orders of magnitude greater than that of water.…”

“…[21][22][23][24][25][26][27] A large solution resistance in the RTIL phase makes it diffcult to obtain voltammograms without distortion, even after applying positive-feedback compensation of the solution resistance. 17,19 For voltammetry in highly resistive media, ultramicroelectrodes are known to be useful. [28][29][30][31][32][33][34][35] In studying charge transfer across the interface between organic solvent-water two-phase systems, a micro liquid-liquid interface formed at the orifice of a capillary or a hole of a thin membrane has been successfully used where the solution resistance in the organic phase is considerably high.…”

Array of water|room temperature ionic liquid micro-interfaces

“…In particular, the group of Kakiuchi has been very active [6][7][8] since their pioneering work in 2003 [9], and the first review paper on this topic was published recently [10]. Ion transfer at the W|RTIL interface is a special case of ion transfer at the interface between two immiscible electrolyte solutions (ITIES), which enables the study and detection of ions not easily oxidisable or reducible at solid|liquid interfaces.…”