Direct Determination of Diffusion Coefficients of Substrate and Product by Chronoamperometric Techniques at Microelectrodes for Any Level of Ionic Support

Hyk, Wojciech; Nowicka, Anna M.; Stojek, Zbigniew

doi:10.1021/ac0109117

Cited by 46 publications

(45 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the linearity of the plot could indicate a small or Fig. 4 absent ohmic drop, migration, or slow interfacial electron transfer during the measurement [17,58] 12 by applying a DPSC [46,47]. This method gives a unique opportunity to estimate the diffusion coefficient of the electrode reaction product generated in the first chronoamperometric step.…”

Section: Determination Of Transport Coefficientsmentioning

confidence: 99%

“…According to our previous work [25,26,45], application of electroanalytical approaches allow us to determine both the concentration (C 0 ) of redox centers and the apparent diffusion coefficient (D app ) for a single crystal of silicotungstic, phosphotungstic acids, or Prussian Blue in a sol-gel matrix, by solving a system of two equations with two unknowns (D app and C 0 ). Moreover, the obtained apparent diffusion coefficients were compared with the values of the real diffusion coefficient (transport coefficient free of migration influence) calculated by using the analysis of transient currents in the double potential step chronoamperometric experiment (DPSC) [46,47]. The great advantage of this method is that determination of the electroreactant's diffusion coefficient and concentration can be performed independently.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Adamczyk

Miecznikowski

2013

J Solid State Electrochem

View full text Add to dashboard Cite

We demonstrate the electrochemical characteristics of the, poorly described in the literature, mixed-valence proton conducting solid borotungstic acid single crystal, H 5 BW 12 O 40 xH 2 O, in the absence of liquid electrolyte phase. We performed electrochemical measurements in an all-solid cell with a gold fiber ultramicrodisk (diameter 10, 25, and 40 μm) working electrode, a silver semi-reference disk electrode, and a glassy carbon ring counter electrode. Diagnostic experiments at different scan rates aimed at probing the model of mass transport and potential kinetic limitations. Such bulk parameters as the effective diffusion coefficient of charge propagation and the concentration of mixed-valence redox centers were determined by two methods. The first method is based on the analysis of both Cottrellian and steady-state currents (the mixed-regimes method), and the second method provides the true diffusion coefficient (transport coefficient free of the migration influence) for both the substrate and the product of the electrode reaction. Together, these methods constitute a double potential step chronoamperometry experiment. The data obtained with these electrochemical experiments (effective diffusion coefficients, concentration of mixed-valence redox centers, etc.) can support the results obtained with other techniques (XRD, FTIR, and TGA).

show abstract

Section: Determination Of Transport Coefficientsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Adamczyk

Miecznikowski

2013

J Solid State Electrochem

View full text Add to dashboard Cite

show abstract

“…This method has been applied to accurate evaluation of D [6][7][8] rather than nc [9]. The advantage has been justified by other research groups [10][11][12][13][14], including apparent potential dependence of n [15,16] and charge transport properties in gels [17]. Since the determination of n, D or c depends not only on selecting a linear domain of the Cottrell plot but also on applied potential and the number of experimental runs [8,15], it is not practical for accurate determination of c. The poor accuracy is ascribed to interference of capacitive current and a delay of a potentiostat.…”

Section: Introductionmentioning

confidence: 99%

Voltammetric Determination of Both Concentration and Diffusion Coefficient by Combinational Use of Regular and Microelectrodes

et al. 2011

View full text Add to dashboard Cite

Two Pt disks with 1.6 and 0.1 mm diameter, whose sizes were accurately evaluated, were applied to voltammetric diffusion-controlled currents to determine the concentrations of redox species. Since voltammetric peak currents at a regular electrode, I p , and limiting currents at a microelectrode, I L , are proportional to D 1/2 and D, respectively, the ratio I p 2 /I L is independent of the diffusion coefficient but dependents on the concentration. We used this fact to determine the concentrations of ferrocenyl derivatives, hemin, hexacyanoferrate(II), dioxygen gas and hydrogen gas. New insights are not only the absolute determination of concentrations but also the sensitive detection of adsorption of electrochemical products which blocked the voltammetric currents.

show abstract

“…22 These species are of different charge numbers, and their molecular sizes are similar. Voltammograms for the oxidation of these molecules/ions recorded in gel and liquid media were well reproducible with the coefficient of variation less than 3%.…”

Section: Resultsmentioning

confidence: 99%

Efficiency of Solute Release from Thermoresponsive Poly(N-isopropylacrylamide) Gels: Electrochemical Studies

et al. 2003

Self Cite

View full text Add to dashboard Cite

An electrochemical method for the simultaneous determination of the diffusion coefficient and efficiency of release of probe species from thermoresponsive gels due to their volume phase transition is presented. The method combines steady-state voltammetry at microelectrodes and conductometry, and it is designed for charged redox species. This method might be modified for uncharged systems; in this case instead of the conductometric measurement an additional independent voltammetric experiment in the solution is required. The approach presented here has been examined for positively and negatively charged and uncharged ferrocene derivatives as probes in the poly(N-isopropylacrylamide) hydrogel. The release coefficient, θ, defined as the ratio of the concentrations of the probe in the expelled solution and the swollen gel, and determined for the charged ferrocene-based probes, is greater by approximately 25% than that found for the uncharged ferrocene derivative. The larger release efficiency for the charged probes is explained in terms of substantial dehydration of polymeric chains during the gel phase transition. The experiments were performed under the conditions of excess supporting electrolyte. No influence of the identity and concentration (up to 0.05 mol/L) of supporting electrolytes (i.e., either LiClO 4 or KCl) on the release coefficient was observed. The average values of release coefficients were determined to be 0.80 ( 0.02, 1.03 ( 0.16, and 1.07 ( 0.14 for 1,1′-ferrocenedimethanol, sodium ferroceneacetate, and ferrocenylmethyltrimethylammonium hexafluorophosphate, respectively.

show abstract

Direct Determination of Diffusion Coefficients of Substrate and Product by Chronoamperometric Techniques at Microelectrodes for Any Level of Ionic Support

Cited by 46 publications

References 25 publications

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Voltammetric Determination of Both Concentration and Diffusion Coefficient by Combinational Use of Regular and Microelectrodes

Efficiency of Solute Release from Thermoresponsive Poly(N-isopropylacrylamide) Gels: Electrochemical Studies

Contact Info

Product

Resources

About