On the interpretation of the potentiometric response of the inert solid electrodes in the monitoring of the oscillatory processes involving hydrogen peroxide

Pękała, K.; Jurczakowski, Rafał; Orlik, Marek

doi:10.1007/s10008-008-0774-1

Cited by 15 publications

(28 citation statements)

References 14 publications

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“…The source of inspiration of the present work was our earlier observation that the potentiometric monitoring of the oscillatory variations of state of the batch H 2 O 2 –NaSCN–NaOH–CuSO 4 oscillator, discovered by Orbán , revealed apparently anomalous antiphase responses of, among others, Au and Pt electrodes . These metals are chemically inert in the studied medium, and therefore it was expected that they would produce perfectly overlapping potential‐time series.…”

Section: Introductionmentioning

confidence: 87%

“…To summarize, although the H 2 O 2 –Na 2 S 2 O 3 –H 2 SO 4 –CuSO 4 system reveals complex and different responses of various sensors, including chemically inert ones, they are not as different as the antiphase characteristics of the oscillations of the Au and Pt electrodes potential for the hydrogen peroxide–thiocyanate system . This means that the explanation of the potentiometric characteristics of the H 2 O 2 –thiosulfate system requires a new analysis, based on the appropriately extended kinetic mechanism, which (i) includes the dynamics of the concentration of Cu(II) ions and (ii) allows to calculate the mixed potential also involving the Cu(II)/Cu(I) redox couple.…”

Section: Comparison Of Responses Of Different Potentiometric Sensorsmentioning

confidence: 99%

“…Assuming, for further simplification, that cathodic ( α ) and anodic (1 – α ) transfer coefficients are for both redox couples equal to 0.5, the explicit expression for the mixed potential is given by

\begin{matrix} true \\ right E_{mix} = \frac{R T}{F} \ln \frac{(||, i_{0, 1}) prefixexp ((), \frac{F E_{1}}{2 R T}) + (||, i_{0, 2}) prefixexp ((), \frac{F E_{2}}{2 R T})}{(||, i_{0, 1}) prefixexp ((), \frac{- F E_{1}}{2 R T}) + (||, i_{0, 2}) prefixexp ((), \frac{- F E_{2}}{2 R T})} \end{matrix}

…”

Section: Comparison Of Responses Of Different Potentiometric Sensorsmentioning

confidence: 99%

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On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

Jędrusiak

Matyszczak

Orlik

2017

Int J of Chemical Kinetics

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The dynamics of the H2O2–Na2S2O3–H2SO4–CuSO4 homogeneous pH oscillator was studied in the flow reactor potentiometrically using different sensors: platinum electrode, Cu(II) ion‐selective electrode (Cu‐ISE), and pH‐electrode. It was found that for the flow rates close to two bifurcation values, between which the oscillations exist, there is a detectable phase shift between the response of the Cu‐ISE and other electrodes, while it practically vanishes for the intermediate flow rates. To explain both the oscillations of the Cu‐ISE potential and the relevant phase shift, the system's dynamics was studied both experimentally and numerically. The literature kinetic mechanism of the pH oscillator was extended for the dynamics of the copper(II) and copper(I) species in the form of thiosulfate complexes, and kinetic parameters of the redox equilibria, ensuring the oscillations, were estimated. It was found that the phase shift at the relatively low flow rates occurs due to limited efficiency of the supply of CuSO4 catalyst, as the species of lowest concentration, to the reactor, and therefore it can be minimized either by increasing the flow rate of all reactants or, alternatively, by enhancing the model concentration of CuSO4 in the feeding stream, for its fixed flow rate. This work is one more proof that it is useful to monitor the dynamics of the homogeneous oscillatory systems with more than one electrode, if the experimental potential–time courses are to be explained in terms of an appropriate kinetic mechanism.

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Section: Introductionmentioning

confidence: 87%

Section: Comparison Of Responses Of Different Potentiometric Sensorsmentioning

confidence: 99%

\begin{matrix} true \\ right E_{mix} = \frac{R T}{F} \ln \frac{(||, i_{0, 1}) prefixexp ((), \frac{F E_{1}}{2 R T}) + (||, i_{0, 2}) prefixexp ((), \frac{F E_{2}}{2 R T})}{(||, i_{0, 1}) prefixexp ((), \frac{- F E_{1}}{2 R T}) + (||, i_{0, 2}) prefixexp ((), \frac{- F E_{2}}{2 R T})} \end{matrix}

…”

Section: Comparison Of Responses Of Different Potentiometric Sensorsmentioning

confidence: 99%

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On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

Jędrusiak

Matyszczak

Orlik

2017

Int J of Chemical Kinetics

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“…Based on the reaction mechanism, one defines "complexes" of species as the objects that appear before and after the reaction arrows, so the network (3,4) contains six such "complexes" (n = 6). Various "complexes" are thus "linked" by the reaction arrows, and in terms of network (3,4), the number of linkage classes l = 2. Finally one defines the reaction vectors in N space, with N = 3 being the number of species; and s = 3, a number of such linearly independent vectors is the smallest number of reactions from which all stoichiometric steps in the mechanism can be constructed as linear combinations of these steps.…”

Section: Dynamic Features Of the Three-variable Kinetic Modelmentioning

confidence: 99%

“…Another complex oscillatory and bistable system, discovered and studied by M. Orbán et al [2,3] as well as later in our group [4][5][6][7][8], involved the oxidation of thiocyanate ions with hydrogen peroxide in an alkaline medium (pH ࣙ 9), in the presence of CuSO- 4 as an initial catalytic species. The original mechanism of Luo et al [3] engaged 26 dynamical variables, from which we extracted simplified nine- [5] and five-variable [9] schemes as the models of the oscillations.…”

Section: Introductionmentioning

confidence: 97%

The Model of “Minimal Oscillator” Derived from the Kinetic Mechanism of the H₂O₂-NaSCN-NaOH-CuSO₄Dynamical System

Jędrusiak

Wiśniewski

Orlik

2015

Int. J. Chem. Kinet.

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Dissipative chemical reactions, which involve oscillatory variations of the concentrations of the intermediates in time, are usually characterized with complicated kinetic mechanisms. However, the essential source of the oscillations can often be reduced to only a few reaction steps providing the alternative domination of the positive and negative feedback loops. In an extreme case such a reduction leads to the so-called "minimal oscillator," the concept used in the past for the well-known Belousov-Zhabotinsky (BZ) reaction. In the present work, we construct such a minimal system for the (discovered by M. Orbán) H 2 O 2 -NaSCN-NaOH-CuSO 4 homogeneous oscillator, in which instabilities originate from kinetic mechanism substantially different from that proposed for the BZ system. The methodology involves intuitive analysis of the reaction mechanism, supported by numerical calculations and spectrophotometric measurements. We show how the actual, only three-variable model evolves from our previously elaborated: nine-and five-variable mechanisms and prove that its further reduction to two-variable one is not possible. Thus the present work is a final step in our searches for the "minimal Orbán oscillator". C 2015 Wiley Periodicals, Inc. Int J Chem Kinet 47: [795][796][797][798][799][800][801][802] 2015

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Investigations of different chemiluminescent peaks in H₂O₂–SCN⁻–Cu²⁺–OH⁻–luminol flow system

et al. 2011

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In the H2O2-SCN(-) -Cu(2+)-OH(-)-luminol oscillatory system of chemiluminescence, the effects of the ingredient concentrations, temperature, flow rate and complexing agent on the oscillatory dynamics were investigated in a continuous-flow stirred tank reactor (CSTR). The dynamical structure of two peaks during a period was discussed in detail. By addition of EDTA to the oscillating system, the peak I height decreased sharply while the peak II height was little affected, and the period kept constant. This may be due to the fast reaction between Cu(II) and EDTA and the highly stable complex Cu(II)-EDTA. From the experimental study and mechanism analysis, the chemiluminescent peak I corresponds to Cu(II) → Cu(I) transformation and the peak II corresponds to the Cu(I) → Cu(II) transformation process. The key species involving in the two-transformation process are inferred to be superoxide radical and hydroxyl radical.

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On the interpretation of the potentiometric response of the inert solid electrodes in the monitoring of the oscillatory processes involving hydrogen peroxide

Cited by 15 publications

References 14 publications

On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

The Model of “Minimal Oscillator” Derived from the Kinetic Mechanism of the H₂O₂-NaSCN-NaOH-CuSO₄Dynamical System

Investigations of different chemiluminescent peaks in H₂O₂–SCN⁻–Cu²⁺–OH⁻–luminol flow system

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On the interpretation of the potentiometric response of the inert solid electrodes in the monitoring of the oscillatory processes involving hydrogen peroxide

Cited by 15 publications

References 14 publications

On the Phase Shifts in the Dynamics of the H2O2–Na2S2O3–H2SO4–CuSO4 Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

On the Phase Shifts in the Dynamics of the H2O2–Na2S2O3–H2SO4–CuSO4 Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

The Model of “Minimal Oscillator” Derived from the Kinetic Mechanism of the H2O2-NaSCN-NaOH-CuSO4Dynamical System

Investigations of different chemiluminescent peaks in H2O2–SCN−–Cu2+–OH−–luminol flow system

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On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

On the Phase Shifts in the Dynamics of the H₂O₂–Na₂S₂O₃–H₂SO₄–CuSO₄ Oscillator Revealed by Comparison of Potentiometric Responses of Different Indicator Electrodes

The Model of “Minimal Oscillator” Derived from the Kinetic Mechanism of the H₂O₂-NaSCN-NaOH-CuSO₄Dynamical System

Investigations of different chemiluminescent peaks in H₂O₂–SCN⁻–Cu²⁺–OH⁻–luminol flow system