The role of the supporting electrolyte cation in the kinetics of outer-sphere electrochemical redox processes involving metal complexes

1981 ◽  
Vol 59 (13) ◽  
pp. 1944-1953 ◽  
Author(s):  
Michael J. Weaver ◽  
H. Y. Liu ◽  
Yongjoo Kim
Keyword(s):  
Double Layer ◽  
Electrode Potential ◽  
Supporting Electrolyte ◽  
Outer Sphere ◽  
Transfer Coefficients ◽  
Trivalent Cations ◽  
Electrochemical Redox ◽  
Kinetics Of ◽  
Charge Formula

The electroreduction rates of Cr(OH2)63+ and Cr(NH3)63+ at the mercury–aqueous interface were monitored as a function of electrode potential in electrolytes containing univalent, divalent, or trivalent cations with systematically varying atomic number in order to scrutinize the role of the supporting electrolyte cation in the kinetics of these simple one-electron outer-sphere electrode reactions. The comparison between the corresponding rate responses for Cr(OH2)63+ and Cr(NH3)63+ reduction brought about by changing the supporting electrolyte cation is expected to provide information on the influence of the cation upon the potential profile in the double layer; despite the close structural and mechanistic similarity of the reactants, the transition state for the latter reaction appears to lie significantly closer to the electrode than that for the former process. The virtues of comparing rate responses at a constant electrode charge density rather than at a constant electrode potential are pointed out. It was found that the variations in the effective average potential at constant charge [Formula: see text]ding changes in the electrode potential [Formula: see text] derived from thermodynamic double-layer measurements. These results, along with the observed variations in the transfer coefficients for the two reactions, are semiquantitatively consistent with a model involving changes in the position of the oHp as the supporting electrolyte cation is altered, but are inconsistent with a model attributing the rate variations to cation specific adsorption.

scholarly journals The Role of the Double Layer for the Pseudocapacitance of the Hydrogen Adsorption on Platinum

2022 ◽  
Author(s):  
Maximilian Schalenbach ◽  
Y. Emre Durmus ◽  
Hermann Tempel ◽  
Hans Kungl ◽  
Rüdiger-A. Eichel
Keyword(s):  
Double Layer ◽  
Hydrogen Adsorption ◽  
Full Range ◽  
Surface States ◽  
Alternative Interpretation ◽  
Kinetics Of Adsorption ◽  
Adsorption Processes ◽  
Kinetics Of ◽  
Cyclic Voltammetry Data

Abstract Pseudocapacitances such as the hydrogen adsorption on platinum (HAoPt) are associated with faradaic chemical processes that appear as capacitive in their potentiodynamic response, which was reported to result from the kinetics of adsorption processes. This study discusses an alternative interpretation of the partly capacitive response of the HAoPt that is based on the proton transport of ad- or desorbed hydrogen in the double layer. Potentiodynamic perturbations of equilibrated surface states of the HAoPt lead to typical double layer responses with the characteristic resistive-capacitive relaxations that overshadow the fast adsorption kinetics. A potential-dependent double layer representation by a dynamic transmission line model incorporates the HAoPt in terms of capacitive contributions and can computationally reconstruct the charge exchanged in full range cyclic voltammetry data. The coupling of charge transfer with double layer dynamics displays a novel physicochemical theory to explain the phenomenon of pseudocapacitance and the mechanisms in thereon based supercapacitors.

Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM)

The Analyst ◽  
2021 ◽  
Author(s):  
Christian Leppin ◽  
Astrid Peschel ◽  
Frederick Sebastian Meyer ◽  
Arne Langhoff ◽  
Diethelm Johannsmann
Keyword(s):  
Double Layer ◽  
Quartz Crystal Microbalance ◽  
Electric Double Layer ◽  
Electrode Potential ◽  
Quartz Crystal ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Kinetics Of ◽  
Viscosity Changes

A fast EQCM measures the kinetics of the viscosity changes inside the double layer following voltage jumps.

scholarly journals Kinetics of electrooxidation of phenol on polycrystalline platinum

2015 ◽  
Vol 17 (2) ◽  
pp. 126-130
Author(s):  
Bogusław Pierożyński ◽  
Grażyna Piotrowska ◽  
Tomasz Mikołajczyk
Keyword(s):  
Ph Dependence ◽  
Supporting Electrolyte ◽  
Charge Transfer Resistance ◽  
Pt Catalyst ◽  
Pt Electrode ◽  
Transfer Resistance ◽  
Polycrystalline Platinum ◽  
Phenol Electrooxidation ◽  
Kinetics Of

Abstract This work reports on kinetics of phenol electrooxidation reaction (PhER), examined at polycrystalline Pt electrode in 0.5 M H2SO4 and 0.1 M NaOH supporting solutions. Important aspects of PhER kinetics were analysed based on potential-dependent, a.c. impedance-derived values of charge-transfer resistance and capacitance parameters. Special attention was also given to the influence of supporting electrolyte ions on the process of phenol oxidation (pH dependence of the PhER), in relation to an important role of anion adsorption on the Pt catalyst surface.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

scholarly journals Association between perinatal factors, genetic susceptibility to obesity and age at adiposity rebound in children of the EDEN mother–child cohort

2021 ◽  
Author(s):  
Aminata Hallimat Cissé ◽  
Sandrine Lioret ◽  
Blandine de Lauzon-Guillain ◽  
Anne Forhan ◽  
Ken K. Ong ◽  
...  
Keyword(s):  
Weight Gain ◽  
Genetic Susceptibility ◽  
Gestational Weight Gain ◽  
Gestational Age ◽  
Obesity Risk ◽  
Perinatal Factors ◽  
Gestational Weight ◽  
Adiposity Rebound ◽  
Kinetics Of

Abstract Background Early adiposity rebound (AR) has been associated with increased risk of overweight or obesity in adulthood. However, little is known about early predictors of age at AR. We aimed to study the role of perinatal factors and genetic susceptibility to obesity in the kinetics of AR. Methods Body mass index (BMI) curves were modelled by using mixed-effects cubic models, and age at AR was estimated for 1415 children of the EDEN mother–child cohort study. A combined obesity risk-allele score was calculated from genotypes for 27 variants identified by genome-wide association studies of adult BMI. Perinatal factors of interest were maternal age at delivery, parental education, parental BMI, gestational weight gain, maternal smoking during pregnancy, and newborn characteristics (sex, prematurity, and birth weight). We used a hierarchical level approach with multivariable linear regression model to investigate the association between these factors, obesity risk-allele score, and age at AR. Results A higher genetic susceptibility to obesity score was associated with an earlier age at AR. At the most distal level of the hierarchical model, maternal and paternal educational levels were positively associated with age at AR. Children born to parents with higher BMI were more likely to exhibit earlier age at AR. In addition, higher gestational weight gain was related to earlier age at AR. For children born small for gestational age, the average age at AR was 88 [±39] days lower than for children born appropriate for gestational age and 91 [±56] days lower than for children born large for gestational age. Conclusion The timing of AR seems to be an early childhood manifestation of the genetic susceptibility to adult obesity. We further identified low birth weight and gestational weight gain as novel predictors of early AR, highlighting the role of the intrauterine environment in the kinetics of adiposity.

scholarly journals Phosphorylation of GAPVD1 Is Regulated by the PER Complex and Linked to GAPVD1 Degradation

2021 ◽  
Vol 22 (7) ◽  
pp. 3787
Author(s):  
Hussam Ibrahim ◽  
Philipp Reus ◽  
Anna Katharina Mundorf ◽  
Anna-Lena Grothoff ◽  
Valerie Rudenko ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Transcriptional Repression ◽  
Small Gtpase ◽  
Main Role ◽  
Interacting Proteins ◽  
Casein Kinase 1 ◽  
Bona Fide ◽  
Kinetics Of

Repressor protein period (PER) complexes play a central role in the molecular oscillator mechanism of the mammalian circadian clock. While the main role of nuclear PER complexes is transcriptional repression, much less is known about the functions of cytoplasmic PER complexes. We found with a biochemical screen for PER2-interacting proteins that the small GTPase regulator GTPase-activating protein and VPS9 domain-containing protein 1 (GAPVD1), which has been identified previously as a component of cytoplasmic PER complexes in mice, is also a bona fide component of human PER complexes. We show that in situ GAPVD1 is closely associated with casein kinase 1 delta (CSNK1D), a kinase that regulates PER2 levels through a phosphoswitch mechanism, and that CSNK1D regulates the phosphorylation of GAPVD1. Moreover, phosphorylation determines the kinetics of GAPVD1 degradation and is controlled by PER2 and a C-terminal autoinhibitory domain in CSNK1D, indicating that the regulation of GAPVD1 phosphorylation is a novel function of cytoplasmic PER complexes and might be part of the oscillator mechanism or an output function of the circadian clock.

Sign in / Sign up

Export Citation Format

Share Document