Galvanostatic study of the kinetics of lithium deposition on platinum electrode in dimethylformamide

1991 ◽  
Vol 56 (1) ◽  
pp. 241-245
Author(s):  
Dafeng Xu ◽  
Shengmin Cai ◽  
Xizun Wu ◽  
Wenzhi Zhang
Keyword(s):  
Electron Transfer ◽  
Metal Surface ◽  
Platinum Electrode ◽  
Deposition Process ◽  
Constant Current ◽  
Rate Determining Step ◽  
Current Pulses ◽  
Lithium Deposition ◽  
Kinetics Of

The deposition of lithium in dimethylformamide (DMF) has been studied by means of galvanostatic measurements. The overpotential was recorded during constant current pulses of so short a duration that only a few monolayers per pulse were deposited. The experiments were carried out under conditions of minimum contamination of the metal surface. The deposition process of Li in DMF is irreversible, the electron transfer being the rate-determining step. A mechanism of Li electrodeposition in DMF was proposed.

scholarly journals Single entity electrochemistry and the electron transfer kinetics of hydrazine oxidation

Nano Research ◽  
2021 ◽  
Author(s):  
Ruiyang Miao ◽  
Lidong Shao ◽  
Richard G. Compton
Keyword(s):  
Electron Transfer ◽  
Bulk Solution ◽  
Relative Contribution ◽  
Rate Determining Step ◽  
Multistep Process ◽  
Ph Range ◽  
Electro Catalytic Oxidation ◽  
Single Particle Impact ◽  
The Impact ◽  
Kinetics Of

AbstractThe mechanism and kinetics of the electro-catalytic oxidation of hydrazine by graphene oxide platelets randomly decorated with palladium nanoparticles are deduced using single particle impact electrochemical measurements in buffered aqueous solutions across the pH range 2–11. Both hydrazine, N2H4, and protonated hydrazine N2H5+ are shown to be electroactive following Butler-Volmer kinetics, of which the relative contribution is strongly pH-dependent. The negligible interconversion between N2H4 and N2H5+ due to the sufficiently short timescale of the impact voltammetry, allows the analysis of the two electron transfer rates from impact signals thus reflecting the composition of the bulk solution at the pH in question. In this way the rate determining step in the oxidation of each specie is deduced to be a one electron step in which no protons are released and so likely corresponds to the initial formation of a very short-lived radical cation either in solution or adsorbed on the platelet. Overall the work establishes a generic method for the elucidation of the rate determining electron transfer in a multistep process free from any complexity imposed by preceding or following chemical reactions which occur on the timescale of conventional voltammetry.

The Oxidation of Dithiocarbamate Anion by Substitution Inert Metal Complexes

1989 ◽  
Vol 42 (7) ◽  
pp. 1085 ◽  
Author(s):  
PJ Nichols ◽  
MW Grant
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Metal Complexes ◽  
Radical Anion ◽  
Outer Sphere ◽  
Aqueous Acetone ◽  
Kinetics Of Oxidation ◽  
Rate Determining Step ◽  
Exchange Rate Constant ◽  
Kinetics Of

The kinetics of oxidation of dithiocarbamate anions to thiuram disulfides in aqueous acetone by {Fe(CN)6}3- and 11 other substitution inert metal complexes have been investigated. Outer-sphere electron transfer, resulting in the formation of dithiocarbamate thio radicals, is the rate determining step. A Marcus cross reaction treatment allows an estimate for the redox potential for the dithiocarbamate radical/anion couple. For diethyldithiocarbamate, E �(edtc/edtc-) = 425 � 33 mV v.s.c.e. and the outer-sphere electron self-exchange rate constant is log kex = 7.0 � 0.3. A comparison with thiophenolate oxidation is also given.

KINETICS OF THE OXIDATION OF MERCURY(I) BY THALLIUM (III) IN AQUEOUS SOLUTION

1957 ◽  
Vol 35 (9) ◽  
pp. 1020-1030 ◽  
Author(s):  
A. M. Armstrong ◽  
J. Halpern
Keyword(s):  
Electron Transfer ◽  
Mercury Atom ◽  
Perchloric Acid Solution ◽  
Transfer Processes ◽  
Rate Determining Step ◽  
Aqueous Perchloric Acid ◽  
The Right ◽  
Electron Transfer Processes ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the oxidation of mercury(I) by thallium(III) in aqueous perchloric acid solution, i.e. Hg(I)2 + Tl(III) → 2Hg(II) + Tl(I), have been examined. The rate law was found to be of the form −d[Hg(I)2]/dt = kexp[Hg(I)2][Tl(III)]/[Hg(II)] where kexp is inversely dependent on the concentrations of H+ and of ClO4−. The rate-determining step of the reaction appears to be a 'two-electron transfer' between a mercury atom, formed by the dismutation of Hg2++, and a hydrolyzed thallium ion, i.e. Hg + TlOH++ → Hg++ + Tl+ + OH−. The rate constant, k, of this reaction is given by k = 1016±2 exp[−14000 ± 3000/RT] liters mole−1 sec.−1.H+ retards the reaction by opposing the hydrolysis of Tl+++, while the effect of ClO4− appears to be due to its complexing with Hg2++, Cl− and Br− catalyze the reaction probably by complexing with Hg++, thus displacing the Hg2++dismutation equilibrium, [Formula: see text], to the right and increasing the concentration of Hg atoms. The kinetics and mechanism of the Tl(I)–Tl(III) isotopic electron exchange reaction and of other electron transfer processes in solution are considered in the light of these observations.

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

Comparison of Gold and Platinum Electrode Responses in Activated Sludge

1993 ◽  
Vol 28 (11-12) ◽  
pp. 473-480
Author(s):  
A. Heduit ◽  
B. Martin ◽  
I. Duchamp ◽  
D. R. Thevenot
Keyword(s):  
Electron Transfer ◽  
Activated Sludge ◽  
Gold Electrode ◽  
Platinum Electrode ◽  
Electrochemical Determination ◽  
Exchange Current ◽  
Experimental Conditions ◽  
Equilibrium Exchange ◽  
Prolonged Contact ◽  
Current Densities

Gold and platinum were compared to ascertain how they expressed a stabilized potential in activated sludge. The comparison was based on electrochemical determination of the electron transfer rate (i.e. equilibrium exchange current density) and recording of potentials against time. When both metals are treated in the same way, platinum gives equilibrium exchange current densities approx. 10 times higher than gold, both in aerated activated sludge and in treated water. For platinum, the equilibrium exchange current densities range from 0.1 to 0.25 µA/cm2 immediately after polishing and decrease during prolonged contact with activated sludge subjected to alternating aeration/anoxia sequences. The lower kinetics of electron transfer on gold go together with significant differences in response:- In an aerobic medium a gold electrode potential is lower than that of a platinum electrode. In a strongly anaerobic medium, the reverse is true. Consequently, the amplitude of the potential variation between aerobic and anaerobic media is smaller for gold than for platinum. Under our experimental conditions this amplitude was approx 350 mV for gold and 850 mV for platinum.- The slopes of the linear relationships between potential and pH or potential and the logarithm of the dissolved oxygen concentration are two or three times greater for platinum than for gold. Although the values obtained with platinum electrodes cannot represent a veritable equilibrium state, the platinum electrode zero-current potential would seem to be far more sensitive to variations in the medium than that of the gold electrode; it is, therefore, more suitable for use in activated sludge.

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