Thermal diffusion of dilute aqueous NH4Cl, Me4NCl, Et4NCl,n-Pr4NCl, andn-Bu4NCl solutions at 25�C

Petit, C.; Hwang, Ming-Hwa; Lin, Jen-Chieh

doi:10.1007/bf00651849

Cited by 9 publications

(8 citation statements)

References 19 publications

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“…The Soret effect affects, for example, mass transport at heated microelectrodes [2], and it can be used to analyze the thermoelectric efficiency of different electrolytes [3]. It can also provide information on the structure of electrolyte solutions [4], or be applied as a tool in biomolecule analytics [5,6] and in polymer separation and purification processes [7,8]. Furthermore, this effect may have played an important role in the origin of life [9].…”

Section: Introductionmentioning

confidence: 99%

“…These include the so-called conductivity method, where changes in conductivity of a non-isothermal cell correspond to changes in concentrations [12][13][14], and the thermoelectric power method, where the initial and steady-state electromotive force of a non-isothermal cell is linked to the heat of transport of the electrolyte [15]. Results achieved with these methods suggest that the Soret coefficients of electrolytes depend strongly on the concentration [15] and size of the transported particles [4]. It has been also suggested that a supporting electrolyte can significantly enhance thermodiffusion in dilute solutions [8], but the hypothesis was not experimentally confirmed due to the lack of a suitable measurement technique.…”

mentioning

confidence: 99%

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Soret coefficient of trace ions determined with electrochemical impedance spectroscopy in a thin cell. Theory and measurement

Jokinen

Manzanares

Murtomäki

2018

Journal of Electroanalytical Chemistry

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The tendency of substance to migrate due to a temperature gradient is known as thermodiffusion or the Soret effect. We believe that this is the first work that describes the study of the Soret effect using electrochemical impedance spectroscopy in a non-isothermal thin cell, and shows how the Soret coefficient can be determined from these measurements. The effect of a temperature gradient in a thin cell is analyzed, both theoretically and experimentally. Our theoretical modeling of the system predicts the effect of key parameters to the impedance spectra. Experimentally we determine the Soret coefficient of the redox couple Fe(CN)6 4− /Fe(CN)6 3− in an aqueous KCl solution. It is found that the Soret coefficient decreases with increasing ionic strength in the studied concentration range.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Soret coefficient of trace ions determined with electrochemical impedance spectroscopy in a thin cell. Theory and measurement

Jokinen

Manzanares

Murtomäki

2018

Journal of Electroanalytical Chemistry

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“…The above-mentioned literature values for Q * i essentially all derive from Soret effect experiments that measured the sum α + +α − [1,7,16,17,45]. From these data, the single-ion Soret coefficients α + and α − were determined either by (arbitrarily) setting α Cl = 0 as a reference point [1] or by the "reduction rule" of Takeyema and Nakashima [18].…”

Section: B Determining Single-ion Soret Coefficients From the Time-dependent Seebeck Coefficientmentioning

confidence: 99%

“…Ionic thermodiffusion can also perturb the local ionic charge number density q(x) = z + ρ + (x) + z − ρ − (x), with z ± being the ionic valencies. Resulting regions of nonvanishing ionic charge density eq(x), with e being the elementary charge, then generate a macroscopic thermoelectric field-the Seebeck effect-that can be measured as the thermovoltage V T between electrodes held at a temperature difference ∆T [16][17][18][19][20][21]; see Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

“…This theoretical finding was at odds, however, with experiments that found that V T (t), indeed, develops fast at first [faster than the experimental resolution (seconds)], but then evolves with the slow timescale τ dif [27,37]. Many authors, therefore, explained the dynamics of V T (t) in terms of the time-dependent salt density c(x, t) [7,16,17,27,33,[45][46][47], shown by Bierlein [48] to evolve with τ dif (see also Refs. [49,50]).…”

Section: Introductionmentioning

confidence: 99%

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On the time-dependent electrolyte Seebeck effect

Sehnem

Janssen

2021

The Journal of Chemical Physics

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Single-ion Soret coefficients αi characterize the tendency of ions in an electrolyte solution to move in a thermal gradient. When these coefficients differ between cations and anions, an electric field can be generated. For this so-called electrolyte Seebeck effect to occur, the different thermodiffusive fluxes need to be blocked by boundaries-electrodes, for example. Local charge neutrality is then broken in the Debye-length vicinity of the electrodes. Confusingly, many authors point to these regions as the source of the thermoelectric field yet ignore them in derivations of the time-dependent Seebeck coefficient S(t), giving a false impression that the electrolyte Seebeck effect is purely a bulk phenomenon. Without enforcing local electroneutrality, we derive S(t) generated by a binary electrolyte with arbitrary ionic valencies subject to a time-dependent thermal gradient. Next, we experimentally measure S(t) for five acids, bases, and salts near titanium electrodes. For the steady state we find S ≈ 2 mV K −1 for many electrolytes, roughly one order of magnitude larger than predictions based on literature αi. We fit our expression for S(t) to the experimental data, treating the αi as fit parameters, and also find larger-than-literature values, accordingly.

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Proton‐Coupled Electron Transfer Aided Thermoelectric Energy Conversion and Storage

Wang

Dai

et al. 2023

Angewandte Chemie

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Low‐grade heat is ubiquitous in the environment and its thermoelectric conversion by the ionic conductors remains a challenge because of the low efficiency and poor sustainability. Here we demonstrate that the thermoelectric performances can be boosted by combining the Soret effect of protons and proton‐coupled electron transfer (PCET) reaction of benzoquinone and hydroquinone in hydrogels. An overall enhancement of thermopower (25.9 mV K−1), power factor (5 mW m−1 K−2), figure of merit (>2.4) and continuity of power output is achieved. Moreover, an energy‐storage function can be achieved by the redox couple, and a retained power output of 27.7 %, or 14 mW m−2 for more than 3 hours is obtained by the re‐balance of PCET reactants in the hydrogel after the removal of the temperature gradient.

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Thermal diffusion of dilute aqueous NH4Cl, Me4NCl, Et4NCl,n-Pr4NCl, andn-Bu4NCl solutions at 25�C

Cited by 9 publications

References 19 publications

Soret coefficient of trace ions determined with electrochemical impedance spectroscopy in a thin cell. Theory and measurement

Soret coefficient of trace ions determined with electrochemical impedance spectroscopy in a thin cell. Theory and measurement

On the time-dependent electrolyte Seebeck effect

Proton‐Coupled Electron Transfer Aided Thermoelectric Energy Conversion and Storage

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