The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Zbigniew Stojek - One of the best experts on this subject based on the ideXlab platform.
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Conditions for purely diffusional transport of charged reactant and charged product in the absence of Supporting Electrolyte
Electrochemistry Communications, 2002Co-Authors: Marcin J. Palys, Zbigniew StojekAbstract:Steady-state currents of charged reactants, at a hemispherical ultramicroelectrode, are independent of the concentration of Supporting Electrolyte if the relationship zR/zP=DR/DP (R=ionic reactant, P=ionic product) is satisfied. Under the above conditions no electric field gradient is present in the solution and no migrational transport takes place. Also, there should be no distortion of the results caused by ohmic drop. The paper presents the theoretical derivation of appropriate equations.
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Voltammetric Investigation of Host–Guest Systems in the Absence of a Supporting Electrolyte
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 1999Co-Authors: Marcin J. Palys, Zbigniew StojekAbstract:In the classic voltammetric approach to host--guest systems the investigations are carried out in excess of a Supporting Electrolyte, i.e., an inactive ionic salt. This approach ensures high electric conductivity of solution and ion migration is avoided. However, the presence of Supporting Electrolyte may introduce competitive equilibria and change activity coefficients, influencing the equilibrium constants using ultramicroelectrodes. Host–guest systems can be studied without addition of Supporting Electrolyte. Under such conditions, the interpretation of experimental results requires a theoretical description that accounts for migrational transport. Such a description is presented in this paper which also shows that migrational effects are so small that they can be neglected for some systems.
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Voltammetric investigation of the complexation equilibria in the presence of a low level of Supporting Electrolyte. Experiments with an inert complex
Analytica Chimica Acta, 1998Co-Authors: Marcin J. Palys, Ewa Rostek, Zbigniew StojekAbstract:Abstract The experimental voltammetric studies of an inert complex has been carried out in the absence of intentionally added Supporting Electrolyte. The chosen system consisted of europium(III) nitrate and 1,4,8,11-tetraazacyclotetradecane (cyclam) in a 4:1 mixture (v/v) of methanol and dimethylsulfoxide. The complex formed is reduced at glassy carbon electrodes at −1.4 V vs. the reference electrode used. The complex stoichiometry is 1:1. The formation constant in the presence of Supporting Electrolyte (0.1 M tetrabutylammonium perchlorate), log β =3.3, has been determined in the usual manner using a glassy carbon electrode. Under the conditions of the absence of excess Supporting Electrolyte, reduction wave height of the Eu 3+ ion depends on concentration of electroinactive ions in the way predicted by the Myland–Oldham theory. The complex stoichiometry (1:1) and the complex formation constant (log β =3.2), in the absence of Supporting Electrolyte, have been determined by nonlinear curve-fitting of the steady-state currents measured at a gold microelectrode for various concentrations of the ligand. A good agreement of these two values supports the theoretical model presented in the previous paper of this series.
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Chronoamperometry of uncharged species under the conditions of deficiency of Supporting Electrolyte: experiment versus theory
Journal of Electroanalytical Chemistry, 1997Co-Authors: Zbigniew StojekAbstract:Abstract Chronoamperometry of ferrocene in acetonitrile containing a small amount of Supporting Electrolyte was studied to verify the theoretical model developed by Hyk et al. (W. Hyk, M. Palys and Z. Stojek, J. Electroanal. Chem., 415 (1996) 13). Some minor extensions were made in this model to adjust it better to the case studied. The experimental chronoamperograms were found to agree well with the theoretical predictions. The biggest deviations were observed for small support ratios. These deviations can be explained by the uncontrolled presence of ionic impurities in the solvent. The impurities influence significantly the conductivity of the solution for support ratios (ratio of concentration of Supporting Electrolyte and ferrocene) smaller than 0.00075, and cannot be included explicitly in the theoretical model. The influence of the geometry of the electrode and the effect of the double layer capacitance are discussed. A possibility of evaluating the total ion level and the formal potential of the system investigated, by fitting an experimental curve to the theoretical one, is also presented.
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Anomalies of staircase voltammetric peaks obtained for the reduction of metal ions in the absence of Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1996Co-Authors: Mikolaj Donten, Zbigniew StojekAbstract:Staircase voltammetric (SCV) peaks for the reduction of metal cations obtained in the absence of Supporting Electrolyte are much less sensitive to the current-sampling parameter α compared with processes having purely diffusional transport and excess Supporting Electrolyte. This is apparently connected with the existence of an increased and changing in time uncompensated resistance. To obtain SCV peaks of identical height to the linear scan peaks, α should be set to 50% or the current should be measured at one half of the pulse time. It has also been demonstrated that, at an intermediate level of Supporting Electrolyte, the staircase waveform apparently generates convectional transport at the surface of a hanging mercury drop electrode.
Janet Osteryoung - One of the best experts on this subject based on the ideXlab platform.
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chronoamperometry of strong acids without Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1999Co-Authors: Koichi Aoki, Aleksander Jaworski, Antonie Baars, Janet OsteryoungAbstract:The steady-state reduction current of the hydrogen ion in a 1:1 strong acid without adding Supporting Electrolyte at a microelectrode is known to be independent of the diffusion coefficient of the anion, although the anion diffuses to the electrode together with the hydrogen ion in order to maintain electroneutrality. This paper aims at resolving this inconsistency of the diffusion of the anion by investigating transient reduction currents of the hydrogen ion without Supporting Electrolyte. The time-dependent diffusion equation associated with migration was solved under the condition of the potential step toward the limiting current-domain at a hemi-spherical electrode. The theoretical transient current has a linear relation with the inverse square root of the time. The anion behaves as if it were electroactive. The slope of the line is expressed by an average of diffusion coefficients of the hydrogen ion and the interacted anion. Chronoamperometric measurements were made in hydrochloric acid including various concentrations of Supporting Electrolyte.
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Voltammetric reduction of hydrogen ion in solutions of polyprotic strong acids with and without Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1997Co-Authors: Malgorzata Ciszkowska, Aleksander Jaworski, Janet OsteryoungAbstract:Abstract Voltammetric reduction of strong polyprotic acids in solutions with excess and without Supporting Electrolyte was studied both theoretically and experimentally. A theoretical model based on the transport (diffusion and migration) equations and the electroneutrality principle was used to compute voltammograms by finite difference simulation under both steady state and transient conditions. Simulated voltammograms are compared with experimental reduction curves obtained at platinum microelectrodes without and with excess Electrolyte for two strong polyprotic acids, sulfuric (H2SO4) and tungstosilicic (H4W12SiO40) acids. Perchloric acid (HClO4) was used as the reference for comparison. The experimental results agree well with the calculated voltammetric curves both without and with excess Supporting Electrolyte. The dependence of voltammetric response on the concentration of acids is also discussed.
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Voltammetry of metals at mercury film microelectrodes in the absence and the presence of varying concentrations of Supporting Electrolyte
Analytical Chemistry, 1995Co-Authors: Malgorzata Ciszkowska, Janet OsteryoungAbstract:The steady-state limiting current for reduction of mono and divalent metal cations to amalgam in solution without Supporting Electrolyte depends on both the charge of the cation and the charge of the associated anion. The ratio of limiting current in the absence of Supporting Electrolyte (i i o ) to diffusional current (i d ) was found to agree well with theoretical predictions (for reduction of M + , 2 and 3/2 for X - and X 2- , respectively, and for M 2+ , 3 and 2 for X - and X 2- , respectively). The reduction current of metal cation depends on the type and concentration of Supporting Electrolyte. The diffusional current is reached at a lower Electrolyte ratio when the cation of the Electrolyte is divalent than when it is monovalent in solutions without Supporting Electrolyte, the limiting current for reduction of a cation having a large negative reduction potential was found to increase in the presence of a cation reducing at a less negative potential. This phenomenon was observed for thallium ion with hydrogen ion and for lead ion with hydrogen ion. The increase of the current is due to the increased rate of transport of the more easily reduced cation at potentials where both reductions are transport-controlled
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Self-Enhancement of Voltammetric Waves of Weak Acids in the Absence of Supporting Electrolyte
Analytical Chemistry, 1994Co-Authors: Zbigniew Stojek, Malgorzata Ciszkowska, Janet OsteryoungAbstract:Weak acids such as acetic, ascorbic, and salicylic acids are easily reduced at platinum microelectrodes in the absence of the Supporting Electrolyte. The current is mass transport controlled, and the reduction of proton is preceded by dissociation of the acid in the reaction layer. Since these acids are only slightly dissociated, transport should not be enhanced by migration and the heights of their voltammetric wave should be nearly independent of Supporting Electrolyte concentration. However, transport-limited currents diminish by 50% when a small amount of a Supporting Electrolyte is added to the solution. Thus the wave height in the absence of Electrolyte exceeds that with Electrolyte present by a factor of 2, as expected for one-electron reduction of a singly charged reactant
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Steady-state voltammetry of strong and weak acids with and without Supporting Electrolyte
Analytical Chemistry, 1992Co-Authors: Malgorzata Ciszkowska, Zbigniew Stojek, Susan E. Morris, Janet OsteryoungAbstract:Voltammetric reduction of perchloric, phosphoric, acetic, and ascorbic acid was investigated under steady-state conditions at platinum- and gold-disk microelectrodes. The dependence of the wave height of proton in perchloric acid on the concentration of Supporting Electrolyte (lithium perchlorate) was compared with the theory for currents limited by migration and diffusion. The wave height depends linearly on hydrogen ion concentration without and with Supporting Electrolyte up to 0.04 and 0.08 M, respectively
Malgorzata Ciszkowska - One of the best experts on this subject based on the ideXlab platform.
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Voltammetric reduction of hydrogen ion in solutions of polyprotic strong acids with and without Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1997Co-Authors: Malgorzata Ciszkowska, Aleksander Jaworski, Janet OsteryoungAbstract:Abstract Voltammetric reduction of strong polyprotic acids in solutions with excess and without Supporting Electrolyte was studied both theoretically and experimentally. A theoretical model based on the transport (diffusion and migration) equations and the electroneutrality principle was used to compute voltammograms by finite difference simulation under both steady state and transient conditions. Simulated voltammograms are compared with experimental reduction curves obtained at platinum microelectrodes without and with excess Electrolyte for two strong polyprotic acids, sulfuric (H2SO4) and tungstosilicic (H4W12SiO40) acids. Perchloric acid (HClO4) was used as the reference for comparison. The experimental results agree well with the calculated voltammetric curves both without and with excess Supporting Electrolyte. The dependence of voltammetric response on the concentration of acids is also discussed.
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Voltammetry of metals at mercury film microelectrodes in the absence and the presence of varying concentrations of Supporting Electrolyte
Analytical Chemistry, 1995Co-Authors: Malgorzata Ciszkowska, Janet OsteryoungAbstract:The steady-state limiting current for reduction of mono and divalent metal cations to amalgam in solution without Supporting Electrolyte depends on both the charge of the cation and the charge of the associated anion. The ratio of limiting current in the absence of Supporting Electrolyte (i i o ) to diffusional current (i d ) was found to agree well with theoretical predictions (for reduction of M + , 2 and 3/2 for X - and X 2- , respectively, and for M 2+ , 3 and 2 for X - and X 2- , respectively). The reduction current of metal cation depends on the type and concentration of Supporting Electrolyte. The diffusional current is reached at a lower Electrolyte ratio when the cation of the Electrolyte is divalent than when it is monovalent in solutions without Supporting Electrolyte, the limiting current for reduction of a cation having a large negative reduction potential was found to increase in the presence of a cation reducing at a less negative potential. This phenomenon was observed for thallium ion with hydrogen ion and for lead ion with hydrogen ion. The increase of the current is due to the increased rate of transport of the more easily reduced cation at potentials where both reductions are transport-controlled
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Voltammetric reduction of polyprotic acids at the platinum microelectrode: dependence on Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1995Co-Authors: Malgorzata Ciszkowska, Zbigniew Stojek, Janet G. OsteryongAbstract:Abstract The voltammetric behavior of weak and strong polyprotic acids was studied at platinum microelectrodes under steady-state conditions in solutions of very low ionic strength, including those without added Supporting Electrolyte. Three diprotic acids (sulfuric, oxalic, and malonic), one triprotic acid (phosphoric acid), and one tetraprotic acid (pyrophosphoric acid) were chosen for the investigation. The reduction of hydrogen ion in solutions of strong diprotic acid (sulfuric acid) with no Supporting Electrolyte results in a voltammetric wave 1.5 times higher than the diffusional wave obtained with excess Electrolyte. This agrees well with the theoretical prediction for one-electron reduction of monovalent cation accompanied by divalent anion. The voltammetric reduction waves of oxalic, malonic, and phosphoric acids in solutions without Supporting Electrolyte were twice as high as the diffusion-controlled waves with excess Electrolyte. This is what theory predicts for a monoprotic strong acid. The strong (H+) and weak (HA− for oxalic and malonic, H2A− for phosphoric, and H2A2− for pyrophosphoric acid) forms of acids are reduced in one (oxalic and malonic) or two (phosphoric and pyrophosphoric) voltammetric waves. The influence of the concentration of Supporting Electrolyte on the height of reduction waves of acids was examined for two kinds of Supporting Electrolyte, with mono- and divalent cations, over a wide range of their concentrations. The experimental results are compared with theoretical predictions. The diffusion coefficients of H(COO)−2 and HCH2(COO)−2 ions were calculated from the steady-state diffusion-controlled currents.
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Self-Enhancement of Voltammetric Waves of Weak Acids in the Absence of Supporting Electrolyte
Analytical Chemistry, 1994Co-Authors: Zbigniew Stojek, Malgorzata Ciszkowska, Janet OsteryoungAbstract:Weak acids such as acetic, ascorbic, and salicylic acids are easily reduced at platinum microelectrodes in the absence of the Supporting Electrolyte. The current is mass transport controlled, and the reduction of proton is preceded by dissociation of the acid in the reaction layer. Since these acids are only slightly dissociated, transport should not be enhanced by migration and the heights of their voltammetric wave should be nearly independent of Supporting Electrolyte concentration. However, transport-limited currents diminish by 50% when a small amount of a Supporting Electrolyte is added to the solution. Thus the wave height in the absence of Electrolyte exceeds that with Electrolyte present by a factor of 2, as expected for one-electron reduction of a singly charged reactant
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Steady-state voltammetry of strong and weak acids with and without Supporting Electrolyte
Analytical Chemistry, 1992Co-Authors: Malgorzata Ciszkowska, Zbigniew Stojek, Susan E. Morris, Janet OsteryoungAbstract:Voltammetric reduction of perchloric, phosphoric, acetic, and ascorbic acid was investigated under steady-state conditions at platinum- and gold-disk microelectrodes. The dependence of the wave height of proton in perchloric acid on the concentration of Supporting Electrolyte (lithium perchlorate) was compared with the theory for currents limited by migration and diffusion. The wave height depends linearly on hydrogen ion concentration without and with Supporting Electrolyte up to 0.04 and 0.08 M, respectively
Richard G. Compton - One of the best experts on this subject based on the ideXlab platform.
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on the adiabaticity of electrode processes effect of the Supporting Electrolyte cation on the kinetics of electroreduction of 3 nitrophenolate
Journal of Electroanalytical Chemistry, 2013Co-Authors: Eduardo Laborda, Christopher Batchelormcauley, Danu Suwatchara, Martin C Henstridge, Richard G. ComptonAbstract:Abstract The comparative analysis of voltammetric responses at different temperatures through the asymmetric Marcus–Hush theory provides physical insight into the changes upon the electron transfer mechanism and the electronic interaction between the electrode and the electroactive species. Herein this approach is applied to the assessment of the influence of the nature of the Supporting Electrolyte on the kinetics of electrode processes. In particular, the electroreduction of the 3-nitrophenolate anion is studied in dimethylsulfoxide solutions via the use of a mercury hemispherical working microelectrode. Three different tetra-alkyl-ammonium perchlorates are employed as Supporting Electrolyte: tetraethylammonium, tetrabutylammonium and tetrahexylammonium. From these kinetic studies undertaken at different temperatures the reorganization energy, force constant symmetry and the strength of the electronic coupling are determined and analyzed for the different conditions. The results presented show a significant effect of the identity of the Supporting Electrolyte cation on the electrode kinetics that can be attributed to the change of the distance of closest approach between the electroactive species and the electrode as well as to ion-pairing effects. The experimental behavior observed suggests that the process has a non-adiabatic character.
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steady state voltammetry at a microdisc electrode in the absence of excess Supporting Electrolyte for reversible quasi reversible and irreversible electrode kinetics
Physical Chemistry Chemical Physics, 2012Co-Authors: Stephen R. Belding, Eduardo Laborda, Richard G. ComptonAbstract:The steady-state voltammetry for a one electron reduction, A + e(-) [symbol:see text] B, is studied at a microdisc electrode in the absence of excess Supporting Electrolyte. For the first time, the full voltammetric waveshape is numerically simulated. Using a combination of theory and experiment, the voltammetry is investigated as a function of two variables: the concentration of the Supporting Electrolyte and the electrochemical rate constant. The 'hemispherical approximation' (in which a microdisc is assumed to be a hemisphere of 2/π the radius) is shown to be valid under weakly supported conditions, for a range of electrochemical rate constants (K0(r(e))/D(A) = 10(-3) - 10(3)). The simulations were used, in conjunction with the Debye-Huckel theory, to rationalise the experimental steady-state voltammetry of two aqueous redox couples: hexaammineruthenium ([Ru(NH(3))(6)](3+)/[Ru(NH(3))(6)](2+)) and hexachloroiridate ([IrCl(6)](2-)/[IrCl(6)](3-)) (each with varying levels of KCl Supporting Electrolyte). This investigation provides evidence for ion pairing between [IrCl(6)](2-)/[IrCl(6)](3-) and K(+) from the Supporting Electrolyte. No observable ion pairing occurs between [Ru(NH(3))(6)](3+)/[Ru(NH(3))(6)](2+) and Cl(-).
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Cyclic voltammetry in the absence of excess Supporting Electrolyte: The effect of analyte charge
Journal of Electroanalytical Chemistry, 2012Co-Authors: Stephen R. Belding, Richard G. ComptonAbstract:Abstract The cyclic voltammetry of the simple electrochemically reversible reduction, A Z A + n e - ⇌ B Z B , is modelled using numerical simulations. The effect of adding different concentrations of Supporting Electrolyte is studied as a function of the scan rate, the diffusion coefficients of species A and B and the diffusion coefficients of the ions in the Supporting Electrolyte. These studies cover the following Z A / Z B redox couples: 2/1, −1/−2, 8/7, and −7/−8. The Supporting information contains a table listing the minimum concentration of Supporting Electrolyte required to achieve fully supported voltammetry pertaining to a range of scan rates ( 10 - 1 ⩽ F ν r e 2 D A RT ⩽ 10 5 ); a wide range of charges of the electroactive species ( - 7 ⩽ Z A ⩽ 8 ) and includes both one and two electron transfer. This allows experimental conditions to be defined so that any particular Nernstian electrochemical system may be studied under diffusion-only conditions without the need for additional experiments and/or simulations.
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voltammetry in the absence of excess Supporting Electrolyte ece disp1 reactions the electrochemical reduction of 2 nitrobromobenzene in acetonitrile solvent
Journal of Electroanalytical Chemistry, 2011Co-Authors: Edward O Barnes, Juan G Limonpetersen, Stephen R. Belding, Yijun Wang, Richard G. ComptonAbstract:Abstract The reduction of 2-nitrobromobenzene in acetonitrile has been studied in the presence and near absence of Supporting Electrolyte at a mercury hemispherical microelectrode. In the presence of a high concentration of tetra- n -butylammonium perchlorate, voltammetric studies over a wide range of voltage scan rates spanning the transition from convergent to linear diffusion confirms the reduction mechanism as DISP1, rather than ECE, as previously thought by the majority of earlier studies. A rate constant of approximately 23 s −1 at 298 K was inferred for the loss of bromide ion from the 2-nitrobromobenzene radical anion. In the presence of weak support, with concentration ratios of Electrolyte to reactant of 5 and 0.5, the Nernst-Planck-Poisson system of equations were used to model the coupled diffusion–migration–reaction. It was found the both the mechanism of reaction and the derived homogeneous kinetics were unchanged in the near absence of Supporting Electrolyte.
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how much Supporting Electrolyte is required to make a cyclic voltammetry experiment quantitatively diffusional a theoretical and experimental investigation
Journal of Physical Chemistry C, 2009Co-Authors: Edmund J F Dickinson, Juan G Limonpetersen, Neil V. Rees, Richard G. ComptonAbstract:Theory is presented for cyclic voltammetry at a hemispherical electrode under conditions where the electric field is nonzero and migration is significant to mass transport. The nonlinear set of differential equations formed by combining the Nernst−Planck equation and the Poisson equation are solved numerically, subject to a zero-field approximation at the electrode surface. The effects on the observed voltammetry of the electrode size, scan rate, diffusion coefficient of electroactive and Supporting species, and quantity of Supporting Electrolyte are noted. Comparison is drawn with experimental voltammetry for the aqueous system [Ru(NH3)6]3+/2+ at a Pt macroelectrode with varying levels of Supporting Electrolyte KCl. The approximations concerned are shown to be applicable where the ratio of Supporting (background) Electrolyte to bulk concentration of electroactive species (support ratio) exceeds 30, and general advice is given concerning the quantity of Supporting Electrolyte required for quantitatively d...
Salvatore Daniele - One of the best experts on this subject based on the ideXlab platform.
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Steady-state voltammetry for hydroxide ion oxidation in aqueous solutions in the absence of and with varying concentrations of Supporting Electrolyte
Analytical Chemistry, 1999Co-Authors: Salvatore Daniele, M. Antonietta Baldo, Carlo Bragato, Guy Denuault, Mmdouh Elsayed AbdelsalamAbstract:The steady-state voltammetric behavior for the oxidation of aqueous solutions containing the strong bases sodium and barium hydroxide was studied with gold microelectrodes in the absence and in the presence of different concentrations of Supporting Electrolyte. A well-defined oxidation wave attributed to the oxidation of hydroxide ions to oxygen was observed in all the solutions investigated, regardless of both the nature of the base and the Supporting Electrolyte employed. However, in solutions with excess Electrolyte, the steady-state limiting current was found to depend on the actual concentration of the Supporting Electrolyte, as the diffusion coefficient of the electroactive species varies with both the ionic strength and viscosity of the medium. Since the hydroxide ion is a negatively charged species, solutions with low or without Supporting Electrolyte yielded currents enhanced by migration contributions. Theoretical equations for the dependence of steady-state limiting currents with ionic strength...
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Steady-state voltammetry for the reduction of labile metal complexes in the absence and presence of different concentrations of Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1997Co-Authors: Salvatore Daniele, Carlo Bragato, M. Antonietta BaldoAbstract:Abstract Steady-state voltammetry for the reduction of labile complexes of lead, cadmium and mercury, in the absence of deliberately added Supporting Electrolyte and with different concentrations of Supporting Electrolyte, has been studied at mercury (lead and cadmium) and platinum disc (mercury) microelectrodes. The effects of ionic strength and nature of an inert Electrolyte on the migrational component, which usually adds to diffusion in the mass transport in solutions with low Electrolyte, have been examined. The results obtained have demonstrated that the ratio of limiting current at different concentrations of Supporting Electrolyte to diffusive limiting current I lm / I ld , depended not only on the charge of the free ion, but also on the amount of labile complexes formed between the metal ion with ligands which may arise from the counter-ion accompanying the metal in its starting salt, from small amounts of Supporting Electrolyte and from the autoprotolysis of water, i.e., OH − . Moreover, the I lm / I ld ratio is affected by the background Electrolyte, which is almost unavoidable in water, and by the hydrolysis of the metal ion which yields protons. A comprehensive theoretical equation, based on already known treatments, has been also derived to predict the limiting current ratios in the presence of all the effects cited above.
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Steady state voltammetry for reduction of cadmium at a Pt microelectrode in dimethylsulphoxide with and without Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1996Co-Authors: Salvatore Daniele, M. Corbetta, M. Antonietta Baldo, Carlo BragatoAbstract:Steady state voltammetry for reduction of cadmium in dimethylsulphoxide (DMSO) with and without Supporting Electrolyte is studied at platinum microdisc electrodes. The ratio of limiting current in absence of Supporting Electrolyte Ilm to diffusive current Ild in DMSO agrees well with theoretical predictions, while comparative measurements carried out in water, under the same condition of Supporting Electrolyte, show some discrepancies. A simple equation is also proposed for predicting the limiting current ratios for the reduction of labile complexes in the absence of Supporting Electrolyte.
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linear sweep and cyclic voltammetry for metal deposition at solid and mercury microelectrodes from solutions with and without Supporting Electrolyte
Journal of Electroanalytical Chemistry, 1994Co-Authors: Salvatore Daniele, M. Corbetta, Maria Antonietta Baldo, Gian Antonio MazzocchinAbstract:Abstract The experimental behaviour under linear sweep and cyclic voltammetry at low scan rates of the reduction of Pb 2+ and Cd 2+ at solid and mercury microelectrodes is reported in the presence and in the absence of Supporting Electrolyte. The major effects observed on decreasing the concentration of Supporting Electrolyte are an increase in the steady-state limiting current and more drawn out curves during the direct scan, broader and asymmetric stripping peaks on the reverse scan. These effects are rationalized in terms of the contributions of migration associated with diffusion in the mass transport and ohmic polarization which adds to concentration polarization when the concentration of Supporting Electrolyte is decreased. The experimental results are also compared with theoretical predictions.
