ChemInform Abstract: Variation of the Heterogeneous Electron Transfer Rate Constant with Solution Viscosity: Reduction of Aqueous Solutions of Cr(III)(EDTA)‐ at a Mercury Electrode.

Zhang, X.; Yang, Hongjun; Bard, Allen J.

doi:10.1002/chin.198732070

Cited by 2 publications

(2 citation statements)

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“…Thus, consideration of eqs 3−5 shows that at a fixed temperature k 0 has a direct theoretical connection to 1/η. 35 This prediction was verified in several early studies undertaken in molecular solvents, 35−37 Recent computational work by Lynden-Bell 38,39 suggests that the Marcus theory applies reasonably well to ionic liquids, although solvent reorganization in these liquids is thought to involve subdiffusive translational motion of the ions, rather than the reorientation associated with molecular solvents. Thus, it might be expected that the influence of viscosity on the heterogeneous kinetics of electrode reactions in these solvents might follow a similar trend to that seen in polar molecular solvents.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Chou

Kurachi

Pan

et al. 2019

ACS Sustainable Chem. Eng.

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Cerium(IV) is often employed as a surrogate for plutonium(IV) in investigations involving the processing of spent nuclear fuel and is an important oxidant in organic synthetic reactions. Surprisingly little is known about the chemistry and electrochemistry of cerium(IV) complexed as [CeCl6]2– in the hydrophobic green ionic liquids that are proposed for these applications such as those based on the bis(trifluoromethylsulfonyl)imide (Tf2N–) anion. Of particular interest is its stability in these ionic liquids in the presence of unbound Cl–. Therefore, the homogeneous pseudo-first-order kinetics of the reaction between [CeCl6]2– and Cl– was investigated in the 1-(1-butyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BuMePyroTf2N) ionic liquid as a function of temperature. These measurements revealed that [CeCl6]2– is surprisingly stable, even at elevated temperatures with a half-life of 44 min at 398 K. Although classed as an outer sphere electron transfer process, the [CeCl6]2–/3– redox reaction exhibits mixed control in this ionic liquid. In order to elucidate the origin of this behavior, detailed measurements of the heterogeneous rate of this reaction were carried out in BuMePyroTf2N and in five additional ionic liquids based on the Tf2N– anion with structurally and chemically distinct cations, including 1-(1-butyl)-3-methylimidazolium (BuMeIm+), tri(1-butyl)methylammonium (Bu3MeN+), 1-butyltrimethylammonium (BuMe3N+), 1-(1-butyl)pyridinium (BuPy+), and 1-ethyl-3-methylimidazolium (EtMeIm+) by using electrochemical impedance spectroscopy (EIS). The heterogeneous rate constants of the [CeCl6]2–/3– reaction at a glassy carbon electrode were found to exhibit a near linear dependence on the absolute viscosity of these ionic liquids, indicating that the rate of this reaction may be controlled by solvent reorganization dynamics in these highly viscous ionic liquids in accordance with contemporary predictions of the Marcus theory of electron transfer. Furthermore, the choice of the organic cation can be used to tune the redox potential of the [CeCl6]2–/3– electrode reaction.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Chou

Kurachi

Pan

et al. 2019

ACS Sustainable Chem. Eng.

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“…The Marcus theory has been widely employed to calculate the rate constants for several electron transfer reactions between donor and acceptor species, and they show excellent agreement with experimental results. 39,40 While purely experimental studies have been done to determine the rate constant of electron transfer reactions in solution, 41 the literature lacks data on the kinetics of electron transfer reactions at the electrode− electrolyte interface. We calculated the electron transfer rate constant for the oxidation of lithium metal in various imidazolium based ionic liquids as the electrolyte.…”

Section: ■ Introductionmentioning

confidence: 99%

Density Functional Theory Based Study of the Electron Transfer Reaction at the Lithium Metal Anode in a Lithium–Air Battery with Ionic Liquid Electrolytes

2014

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Room temperature ionic liquids, which have unique properties such as a relatively wide electrochemical stability window and negligible vapor pressure, are promising candidates as electrolytes for developing lithium–air batteries with enhanced performance. The local current density, a crucial parameter in determining the performance of lithium–air batteries, is directly proportional to the rate constant of the electron transfer reaction at the surface of the anode that involves the oxidation of pure lithium metal into lithium ion (Li+). The electrochemical properties of ionic liquid based electrolytes, which can be molecularly tailored on the basis of the structure of their constituent cations and anions, play a crucial role in determining the reaction rate at the anode. In this paper, we present a novel approach, based on Marcus theory, to evaluate the effect of varying length of the alkyl side chain of model imidazolium based cations on the rates of electron transfer reaction at the anode. Density functional theory was employed for calculating the necessary free energies for intermediate reactions. Our results indicate that the magnitude of the Gibbs free energy of the overall reaction decreases linearly with the inverse of the static dielectric constant of the ionic liquid, which in turn corresponds with an increase in the length of the alkyl side chain of the ionic liquid cation. Nelsen’s four-point method was employed to evaluate the inner sphere reorganization energy. The total reorganization energy decreases with increase in the length of the alkyl side chain. Finally, the rate constants for the anodic electron transfer reaction were calculated in the presence of varying ionic liquid based electrolytes. The overall rate constant for electron transfer increases with increase in the static dielectric constant. The presented results provide important insight into identification of appropriate ionic liquid electrolytes to obtain enhanced current densities in lithium–air batteries.

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ChemInform Abstract: Variation of the Heterogeneous Electron Transfer Rate Constant with Solution Viscosity: Reduction of Aqueous Solutions of Cr(III)(EDTA)‐ at a Mercury Electrode.

Cited by 2 publications

References 1 publication

Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Density Functional Theory Based Study of the Electron Transfer Reaction at the Lithium Metal Anode in a Lithium–Air Battery with Ionic Liquid Electrolytes

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ChemInform Abstract: Variation of the Heterogeneous Electron Transfer Rate Constant with Solution Viscosity: Reduction of Aqueous Solutions of Cr(III)(EDTA)‐ at a Mercury Electrode.

Cited by 2 publications

References 1 publication

Thermodynamics and Electron Transfer Kinetics of the [CeCl6]2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Thermodynamics and Electron Transfer Kinetics of the [CeCl6]2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Density Functional Theory Based Study of the Electron Transfer Reaction at the Lithium Metal Anode in a Lithium–Air Battery with Ionic Liquid Electrolytes

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Product

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Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids

Thermodynamics and Electron Transfer Kinetics of the [CeCl₆]^2–/3– Redox Reaction in a Series of Bis(trifluoromethylsulfonyl)imide-Based Room Temperature Ionic Liquids