scholarly journals Kinetics of V5+/V4+ Redox Reaction – Butler-Volmer and Marcus Models

2021 ◽  
Author(s):  
Anand Kumar Tripathi ◽  
Miji E Joy ◽  
Debittree Choudhury ◽  
Rubul Das ◽  
Manoj Neergat
Keyword(s):  
Redox Reaction ◽  
Reorganization Energy ◽  
Potential Drop ◽  
Limited Range ◽  
Electrochemical Kinetics ◽  
Back Reaction ◽  
Cyclic Voltammograms ◽  
Transfer Resistance ◽  
Tafel Slope ◽  
Kinetics Of

Abstract Kinetics of the V5+/V4+ redox reaction on Vulcan XC-72 modified glassy carbon disk electrode is investigated in a three-electrode configuration. Cyclic voltammograms of V5+/V4+ redox couple suggest that the overpotential range for the kinetic analysis is limited to ±300 mV, after excluding V4+/V3+ redox reaction at the negative overpotential and the oxygen evolution reaction at the positive overpotential. Therefore, the linear sweep-voltammograms (LSVs) are corrected for potential drop due to solution resistance (iRs), mass-transfer resistance, and most importantly, for the back reaction current. These corrections are imperative to estimate the Tafel slope in the limited range of overpotential for V5+/V4+ redox reaction. The charge-transfer coefficient (α) estimated from the Tafel slope deviates significantly from the expected value of 0.5 for the single electron-transfer reaction. Moreover, the instantaneous slope of the Tafel plot suggests that the α is overpotential dependent. Therefore, Marcus theory of electrochemical kinetics is applied to estimate the α. The reorganization energy (λ) calculated from the Arrhenius plots is in the range of values reported in the literature for the other redox couples.

scholarly journals Kinetics of electrochemical intercalation of lithium ion into Li[Li0.2Co0.3Mn0.5]O2 electrode from Li2SO4 solution

2021 ◽  
Vol 23 (09) ◽  
pp. 656-687
Author(s):  
K.C. Mahesh ◽  
◽  
G.S. Suresh ◽  
Keyword(s):  
Aqueous Electrolyte ◽  
Lithium Ion ◽  
Potential Drop ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Ohmic Potential Drop ◽  
Ion Intercalation ◽  
Time Invariant ◽  
Kinetics Of ◽  
Titration Technique

The kinetics of electrochemical lithium ion intercalation into Li[Li0.2Co0.3Mn0.5]O2 electrode in 2 M Li2SO4 aqueous electrolyte has been studied using two electroanalytical methods, namely, potentiostatic intermittent titration technique (PITT) and galvanostatic intermittent titration technique (GITT). The results are compared with those from nonaqueous electrolytes. Layered, lithium-rich Li[Li0.2Co0.3Mn0.5]O2 cathode material was synthesized by reactions under autogenic pressure at elevated temperature (RAPET) method. The effects of ohmic potential drop and charge-transfer resistance have been considered while predicting the current transients obtained with aqueous electrolyte. For PITT and GITT, we have defined their characteristic time-invariant functions, It1/2 and dE/dt1/2, respectively to present the diffusion time constant τ. Application of different theoretical diffusion models for treating the results obtained by the above-mentioned techniques allowed us to calculate the diffusion coefficient of lithium ions (D) at different potentials (E). The intercalation process is explained by considering the possible attractive interactions of the intercalated species in terms of Frumkin intercalation isotherm. We have observed a strictcorrespondence between the peaks of the intercalation capacitance and the minima in the corresponding log D vs. E curve.

Electrochemical Kinetics of Ag|Ag+and TMPD|TMPD+•in the Room-Temperature Ionic Liquid [C4mpyrr][NTf2]; toward Optimizing Reference Electrodes for Voltammetry in RTILs

2007 ◽  
Vol 111 (37) ◽  
pp. 13957-13966 ◽  
Author(s):  
Emma I. Rogers ◽  
Debbie S. Silvester ◽  
Sarah E. Ward Jones ◽  
Leigh Aldous ◽  
Christopher Hardacre ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Electrochemical Kinetics ◽  
Reference Electrodes ◽  
Kinetics Of

Unraveling improved electrochemical kinetics of In2Te3-based anodes embedded in hybrid matrix for Li-ion batteries

2022 ◽  
Vol 429 ◽  
pp. 132395
Author(s):  
Seongjoon So ◽  
Jaewook Ko ◽  
Yong Nam Ahn ◽  
Il Tae Kim ◽  
Jaehyun Hur
Keyword(s):  
Electrochemical Kinetics ◽  
Li Ion Batteries ◽  
Hybrid Matrix ◽  
Li Ion ◽  
Kinetics Of

Bioelectrocatalysis: the electrochemical kinetics of hydrogenase action

1993 ◽  
Vol 27 (3) ◽  
pp. 331-339 ◽  
Author(s):  
S.D. Varfolomeyev ◽  
A.I. Yaropolov ◽  
A.A. Karyakin
Keyword(s):  
Electrochemical Kinetics ◽  
Kinetics Of

Dependence of Film Thickness on Electrochemical Kinetics of Polypyrrole and on Lithium/Polypyrrole Battery

1986 ◽  
Vol 15 (10) ◽  
pp. 1687-1690 ◽  
Author(s):  
Tetsuya Osaka ◽  
Katsuhiko Naoi ◽  
Satoshi Ogano ◽  
Sadako Nakamura
Keyword(s):  
Film Thickness ◽  
Electrochemical Kinetics ◽  
Kinetics Of

scholarly journals Modeling of the adsorption kinetics of zinc onto granular activated carbon and natural zeolite

2006 ◽  
Vol 71 (8-9) ◽  
pp. 957-967 ◽  
Author(s):  
Ljiljana Markovska ◽  
Vera Meshko ◽  
Mirko Marinkovski
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Simulation Study ◽  
Natural Zeolite ◽  
Granular Activated Carbon ◽  
Model Parameters ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Kinetics Of

The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC) and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II) from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model) combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, two model parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II) concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II) - adsorbent system, k f was constant, except for the lowest initial concentration, while D s was found to increase with increasing initial Zn(II) concentration.

scholarly journals Carbon Nanotube Electrodes for Electrochemical Detection of Dopamine

2021 ◽  
Author(s):  
Gaurang Khot ◽  
Frank Platte ◽  
Neil Shirtcliffe ◽  
Tansu Celikel
Keyword(s):  
Electron Transport ◽  
Pyrolytic Carbon ◽  
Transport Kinetics ◽  
Electrochemical Kinetics ◽  
Current Voltage ◽  
Surface Diameter ◽  
Kinetics Of ◽  
The Brain ◽  
Anodic Region ◽  
Basal Concentration

AbstractCarbon nanotubes (CNTs) are suited for neurochemistry because of their biological inertness, ability to withstand biofouling, and superior electron transport kinetics. Dopamine, the canonical monoaminergic neuromodulator, contributes to reward, cognition and attention, however, its detection in real-time is challenging due to its low basal concentration in the brain (100nM L-1). In our present work, we fabricate pyrolytic carbon electrodes and perform a CNT coating to improve the electrochemical kinetics of dopamine. Upon CNTs coating, dopamine shows a sensitivity of 9±18nA/μM for a cylindrical electrode having a mean surface diameter of 8±4μm. Increasing the scan frequency from 10-100 Hz shows that dopamine electron transfer kinetics improves; wherein dopamine is oxidized at 0.35±0.09V and reduced to -0.10±0.05V for 10 Hz. Increasing the frequency results in a shift of oxidation peak towards the anodic region, wherein dopamine oxidizes at 0.08±3V and reduces at -0.1±0.05V for 100 Hz, thus showing that dopamine redox is reversible which can be attributed to the superior electron transport kinetics of CNTs. The sensor was able to distinguish dopamine signals against other neurochemicals like serotonin and foulant 3,4-Dihydroxyphenylacetic acid (DOPAC). The minimum chemical detection that can be performed using these nanopipettes is 50±18nM L-1, which is well below the physiological concentrations of dopamine in the brain.Graphical AbstractA: Pictorial view of background-subtracted voltammetry. The waveform used was -0.4V to 1.3 V and cycled back to -0.4V at 10 Hz. B: The voltammogram was converted as a 2-D representation, into current, voltage, and repetition to understand the dopamine oxidation. C: Background subtracted voltammetry for dopamine using 100 Hz waveform. D: The 2-D representation of current, voltage, and repetition.

Tidying up the environment: A journey from exponential curves to hydrodynamics in environmental batch dissolutions

2011 ◽  
Vol 83 (5) ◽  
pp. 1113-1128 ◽  
Author(s):  
Victor W. Truesdale
Keyword(s):  
Back Reaction ◽  
Middle Ground ◽  
Rotating Disc ◽  
Hydrodynamic Approach ◽  
Batch Dissolution ◽  
Global Consistency ◽  
Great Excess ◽  
Calcium Carbonate Dissolution ◽  
Environmental Work ◽  
Kinetics Of

This paper reviews progress made over the last decade with the shrinking object approach to the kinetics of batch dissolution. It demonstrates how the O’Connor–Greenberg equation leads to three dissolutions: those that remain well undersaturated, those that saturate with a great excess of solid left-over, and those in the middle ground where saturation is approached or attained, but where much of the solid originally added dissolves. The equations that describe these conditions are discussed, alongside sample results that validate their use with test substances, for example, salts, sucrose, silica gel, and gypsum. The equations are then shown to be consistent with the hydrodynamic approach to dissolution. Finally, further work with middle-ground dissolutions of gypsum lead to a mechanism for the back-reaction, which involves the CaSO40 ion-pair. After comparison with existing studies of calcium carbonate dissolution, it is argued that this is a universal mechanism for salt dissolutions. The work improves batch dissolution as a technique to the point where it can be used synergistically with chemo-stat and rotating disc approaches. Suggestions are made for greater standardization in dissolution conditions, especially in environmental work where the data collected has to have global consistency.

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