scholarly journals The kinetics of electrode reactions. I and II

1938 ◽  
Vol 169 (937) ◽  
pp. 206-234 ◽  
Keyword(s):  
Electrode Potential ◽  
Surface Reaction ◽  
Reference Electrode ◽  
Electrode Reaction ◽  
Potential Difference ◽  
Concentration Difference ◽  
Electrode Processes ◽  
Electrode Reactions ◽  
Concentration Changes ◽  
Kinetics Of

In any surface reaction taking place in a Solution, it is clear that the concentration of the reactants in the vicinity of the surface must fall. If the concentration in the bulk of the solution remains constant, a steady state may finally be reached, in which the rate of replenishment of the solution in this region, from the bulk, is equal to the rate at which the reactant in question is used up. But, in general, such a state is only attained when the concentration at the surface is less than that in the rest of the solution. If the reaction considered is an electrode reaction, these concentration changes may affect the electrode potential. This question is therefore of importance in the study of overpotential, and of the kinetics of electrode processes generally. The overpotential at an electrode is defined as the potential difference between this electrode and a similar unpolarized reversible electrode in the same solution. In practice this reference electrode is usually situated outside the region affected by the concentration changes near the electrode at which the reaction is taking place. The measured potential difference between the two electrodes, i.e. the measured overpotential, may therefore include a term due to the concentration difference.

The Kinetics of Electrode Reactions on Metallic Bismuth in Pure Molten Bismuth Chloride

1992 ◽  
Vol 57 (5) ◽  
pp. 1015-1022
Author(s):  
Adolf Kisza ◽  
Jerzy Każmierczak
Keyword(s):  
Activation Parameters ◽  
Electrode Reaction ◽  
Molten Chlorides ◽  
Electrode Reactions ◽  
Metallic Bismuth ◽  
Kinetics Of ◽  
Bismuth Chloride

The relaxation and impendance methods were applied to the study of electrode reaction on bismuth electrode immersed in pure molten bismuth chloride. The found kinetic and activation parameters are compared with the similar ones for other pure molten chlorides.

Significance of effects of pressure on electrode reactions. Part III. Equilibrium processes at reference electrodes and the volume of H in Pd

1978 ◽  
Vol 56 (7) ◽  
pp. 915-924 ◽  
Author(s):  
Brian E. Conway ◽  
J. C. Currie
Keyword(s):  
Pressure Range ◽  
Volume Changes ◽  
Reference Electrodes ◽  
Pressure Coefficients ◽  
Electrode Processes ◽  
Elevated Pressures ◽  
Electrode Reactions ◽  
Equilibrium Processes ◽  
Pressure Bomb ◽  
Kinetics Of

For studies on effects of pressure on kinetics of electrode processes (Parts I, II), reversible reference electrodes suitable for use in a completely enclosed high-pressure bomb are required. The electrodes must exhibit reversible behaviour over the pressure range employed in the experiments, i.e., their changes of emf with increasing and decreasing changes of pressure must be reproducible and correspond to the respective volume changes in the reactions.A series of reversible reference electrodes is examined over a range of pressures up to ca. 2500 bars. The Pd–H/H+ and Ag, AgCl/Cl− reference electrodes are found to behave very satisfactorily at elevated pressures; the Pt,H2/H+ electrode is, however, less satisfactory, due to problems associated with dissolved H2.The results enable the volume of Pd–H and of H sorbed into Pd to be evaluated, together with estimates of the partial molar volume of H2 in aqueous HCl. These data enable the pressure-coefficients of metal–solution potential differences at individual reference electrodes to be evaluated. Such information is required for interpretation of effects of pressure on kinetics of electrode processes.

Kinetics of Electrochemical Reductive Dissolution of Iron(III) Hydroxy-oxides

1995 ◽  
Vol 60 (8) ◽  
pp. 1261-1273 ◽  
Author(s):  
Tomáš Grygar
Keyword(s):  
Rate Constants ◽  
Electrode Potential ◽  
Surface Reaction ◽  
Stripping Voltammetry ◽  
Dissolution Process ◽  
Reductive Dissolution ◽  
Working Electrode ◽  
Natural Iron ◽  
Kinetics Of

Abrasive stripping voltammetry was applied to the chronoamperometric and voltammetric investigation of the kinetics of reductive dissolution of synthetic and natural iron(III) hydroxy-oxides. Conditions were found under which the dissolution process can be described by equations derived for and applied to the surface reaction of the particles. The rate constants obtained were employed to compare the electrochemical and chemical reductive dissolution and to quantitatively evaluate the effect of adsorbing ions, pH, and working electrode potential.

Pressure effects and solvent dynamics in the electrochemical kinetics of the tris(hexafluoroacetylacetonato)ruthenium(III)/(II) couple in nonaqueous solvents

2001 ◽  
Vol 79 (5-6) ◽  
pp. 841-847 ◽  
Author(s):  
Jinkui Zhou ◽  
Thomas W Swaddle
Keyword(s):  
Free Energy ◽  
Activation Barrier ◽  
Electrode Reaction ◽  
Pressure Effects ◽  
Electrochemical Kinetics ◽  
Free Energy Barrier ◽  
Exchange Reactions ◽  
Electrode Processes ◽  
Solvent Dynamics ◽  
Kinetics Of

Rate constants and reactant diffusion coefficients for the Ru(hfac)30/– electrode reaction have been measured at 25°C as functions of pressure (0-200 MPa) in acetone, acetonitrile, methanol, and propylene carbonate. In sharp contrast to the negative volumes of activation ΔVex‡ found for the corresponding bimolecular self-exchange reaction in organic solvents, the volumes of activation ΔVel‡ for the electrode reaction are markedly positive, ranging from 8 to 12 cm3 mol–1. The volumes of activation ΔVdiff‡ for reactant diffusion (which can be equated to the volume of activation ΔVvisc‡ for viscous flow) range from 12 to 19 cm3 mol–1. For the Debye solvents acetonitrile and acetone at least, ΔVel‡ is given within the experimental uncertainty by ΔVdiff‡ + (ΔVex‡/2). In this relation, the numerical value of ΔVdiff‡ represents indirectly the dominant contribution of solvent dynamics (solvent friction) to ΔVel‡, and ΔVex‡/2 represents the pressure dependence of the free-energy barrier height for the electrode reaction. It is proposed that solvent friction is important in nonaqueous electrode processes but not in the corresponding bimolecular self-exchange reactions because the free-energy activation barrier is twice as high in the latter.Key words: electrode reaction kinetics, solvent dynamics, electron transfer mechanisms, pressure effects, volume of activation.

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