Electromotive Force of Electrolytic Thermocouples and Thermocells and the Entropy of Transfer and Absolute Entropy of Ions

Eastman, E. D.

doi:10.1021/ja01389a008

Cited by 55 publications

(44 citation statements)

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“…Although only relative rather than absolute values of d&lj,/dT are thermodynamically accessible, there is ample evidence that indicates that for most aqueous electrolytes, d@,i,/dT 5 50 q V deg-l 20. 21 For strongly acidic or alkaline media, markedly larger values of d@tl,/dT are obtained2Ib which recall the large isothermal liquid junction potentials which can be generated in media containing H + or O H -ions. DeBethune ct al.…”

Section: Methodsmentioning

confidence: 85%

“…~~ For the present purposes, the most convenient method involves the use of nonisothermal electrochemical cells. 20,21 In this arrangement, the temperature of the half-cell containing the redox couple of interest is varied while the temperature of the other half-cell consisting of some convenient reference electrode is held constant. *' One such cell arrangement that was commonly used in the present work can be written as The measured temperature coefficient d E p i / d T of the overall (formal) potential Epi across such a nonisothermal cell which is reversible to the couple M1I1/l1 can be separated into various components as in the equation @,I, is the Galvani potential difference across the thermal liquid junction within the KCI salt bridge, 4Jtc is the "thermocouple" potential difference between the hot and cold regions of the mercury working electrode, E?'…”

Section: Methodsmentioning

confidence: 99%

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A survey of ligand effects upon the reaction entropies of some transition metal redox couples

Yee¹,

Cave²,

Guyer³

et al. 1979

J. Am. Chem. Soc.

326

297

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Abstract:The reaction entropies lSo,, of a number of transition metal redox couples of the form M(III)/( 11) in aqueous solution have bcen determined using nonisothermal electrochemical cells in order to explore the effect of varying the ligand structure upon the nature of the ion-solvent interactions. Examination of six aquo couples of the form M ( O H Z ) , ,~+ '~+ with varying metal M yielded ASo,, values in the range 36-49 eu. In order to scrutinize the effect of replacing aquo with ammine and simple anionic ligands, R u ( l I I ) / ( I I ) couples were employed since the relativc substitution inertness of both oxidation states allowed AS',, to be determined using cyclic voltammetry. The stepwise replacement of aquo by ammine ligands results in substantial reductions in ASo,, which are attributed to the smaller extent of ligand-solvent hydrogen bonding for ammine compared with aquo ligands. Substitution of both aquo and ammine by anionic ligands also resulis in substantial reductions in ASo,,. A number of M(III)/(II) couples containing chelating ligands were also examined. Sizable differcnces in ASo,, were found between Co(lll)/(ll) couples and the corresponding R u ( l l l ) / ( l l ) and Fe(lll)/(ll) couples. Suggested explanations are differences in ligand conformation and electron delocalization effects. The possible contribution of outer-sphere solvent structuring effects to the large reorganization energies observed for electron exchange of aquo complexes is noted. The validity of the assumptions required for the estimation of ASo,, from nonisothermal cell measurements is discussed.

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Section: Methodsmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

A survey of ligand effects upon the reaction entropies of some transition metal redox couples

Yee¹,

Cave²,

Guyer³

et al. 1979

J. Am. Chem. Soc.

326

297

View full text Add to dashboard Cite

show abstract

“…DT is far less than T) (Eastman, 1928a(Eastman, , 1928b, and 3) the size of diffusing species is small (cannot be large polymers or super-molecules).…”

Section: Local Thermodynamic Equilibrium (Lte) Methodsmentioning

confidence: 99%

A theoretical model of isotopic fractionation by thermal diffusion and its implementation on silicate melts

Liu

2015

Geochimica et Cosmochimica Acta

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“…where the magnitude and sign of S e are determined by the ∆S rxn for a given redox reaction [38,39]. One of the reasons for choosing Fe(CN) 6 3− /Fe(CN) 6 4− as the thermocell redox couple is that it provides a relatively high entropy change (~137 J/mol•K) corresponding to a high S e of~1.42 mV/K, which is almost one order of magnitude higher than the Seebeck coefficient of thermoelectric materials [40].…”

Section: Evaluation Of Thermocell Performancementioning

confidence: 99%

Thermocells for Hybrid Photovoltaic/Thermal Systems

et al. 2020

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The photovoltaic conversion efficiency of solar cells is highly temperature dependent and decreases with increasing temperature. Therefore, the thermal management of solar cells is crucial for the efficient utilization of solar energy. We fabricate a hybrid photovoltaic/thermocell (PV/T) module by integrating a thermocell directly into the back of a solar panel and explore the feasibility of the module for its practical implementation. The proposed PV/T hybrid not only performs the cooling of the solar cells but also produces an additional power output by converting the heat stored in the solar cell into useful electric energy through the thermocell. Under illumination with an air mass of 1.5 G, the conversion efficiency of the solar cell can improve from 13.2% to 15% by cooling the solar cell from 61 °C to 34 °C and simultaneously obtaining an additional power of 3.53 μW/cm2 from the thermocell. The advantages of the PV/T module presented in this work, such as the additional power generation from the thermocell as well as the simultaneous cooling of the solar cells and its convenient installation, can lead to the module’s importance in practical and large-scale deployment.

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Electromotive Force of Electrolytic Thermocouples and Thermocells and the Entropy of Transfer and Absolute Entropy of Ions

Cited by 55 publications

References 0 publications

A survey of ligand effects upon the reaction entropies of some transition metal redox couples

A survey of ligand effects upon the reaction entropies of some transition metal redox couples

A theoretical model of isotopic fractionation by thermal diffusion and its implementation on silicate melts

Thermocells for Hybrid Photovoltaic/Thermal Systems

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