Theory of Successive Electron Transfer Steps in Cyclic Voltammetry: Application to Oxygen Pseudocapacitance on Platinum

Appleby, A.J.

doi:10.1149/1.2403662

Cited by 59 publications

(25 citation statements)

References 8 publications

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“…300~ with a molten electrolyte (11,12) down to low temperatures with aqueous solutions (4)(5)(6)(7)(8)(9). The simplest way to study the aging effects is to form a fixed amount of oxygen-containing species by applying a linear anodic potential sweep to leave the circuit open for a certain lapse of time and finally to electroreduce the species with a linear potential sweep (5,6,13).…”

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confidence: 99%

Kinetics of Aging of the Oxygen Monolayer on Platinum under a Complex Potentiodynamic Perturbation Program

Folquer

Zerbino

Tacconi

et al. 1979

J. Electrochem. Soc.

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The dynamic aging of the oxygen-containing species electrosorbed on platinum in sulfuric acid solutions in the region of the monolayer produces three energetically different Pt(O) species, which are revealed by running cathodic potentiodynamic scans. The dynamic aging process is described by a second-order rate equation. It depends on the perturbation frequency and on the number of potential scans related to the aging process. The results also show a possible penetration of oxygen into the metal to the depth of the first and second crystallographic layers. A reaction scheme is proposed to explain the existence of the different species. The kinetic behavior is interpreted tnrougr~ a model where all the reacting particles are dynamically coupled to the fast electrochemical perturbation.The potentiodynamic electroformation and electroreduction of the oxygen-containing monolayer on platinum ha~ been studied for a long time. Reviews on the subject have recently been published (1-3). Both processes are relatively complex since the electrochemical reactions are coupled to chemical reactions related to changes of the structural configuration of the film. The shapes of the resulting cathodic and anodic Eli profiles were quantitatively treated in terms of coverage of the electrode by oxygen species and time-dependent rearrangement effects (4-6).Another approach to the subject of the film irreversibility on platinum within the potential range of the monolayer electroformation and electrodesorption was given in terms of exponentially diminishing rate constants in both anodic and cathodic directions, resulting from surface rearrangement and film aging (7). The existence of two electrochemically distinguishable O-species on the surface was also demonstrated (8). More recently, the hysteresis phenomena related to the formation of oxygen-containing species at platinum anodes were explained through a growth model based on rate-determining nucleation (9, 10).The aging of the oxygen-containing monolayer occurs at any temperature ranging from ca. 300~ with a molten electrolyte (11, 12) down to low temperatures with aqueous solutions (4-9). The simplest way to study the aging effects is to form a fixed amount of oxygen-containing species by applying a linear anodic potential sweep to leave the circuit open for a certain lapse of time and finally to electroreduce the species with a linear potential sweep (5,6, 13). The aging effect produces a net shift of the characteristic electroreduction current peak toward more cathodic potential values. This can be denoted as the open-circuit (static) aging of the species. Another way of producing an equivalent effect is by means of three successive trains of triangular potential sweeps (14). The first train at the potential sweep rate, v, covers the complete potential range related to both the electrooxidation and electroreduction of the oxygen-containing monolayer. With the first train a stable and reproducible Eli profile is achieved. The second train is usually faster than the former and the ...

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confidence: 99%

Kinetics of Aging of the Oxygen Monolayer on Platinum under a Complex Potentiodynamic Perturbation Program

Folquer

Zerbino

Tacconi

et al. 1979

J. Electrochem. Soc.

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“…The decrease of the anodic peak current of the first redox step is also associated with the increase of the peak-to-peak separation by the response of the first redox process. This is a typical feature for the occurrence of the chemical reaction to the product of the first electron transfer step [6,14,[27][28][29][30]. The features of the cyclic voltammograms shown in Fig.…”

Section: Resultsmentioning

confidence: 83%

“…The differences between these techniques exist in the form of the potential ramp, but also in the measuring manner [1]. In the linear cyclic voltammetry the working electrode potential is ramped linearly vs. time [1, [26][27][28]. When the potential ramp in cyclic voltammetry reaches a given end value, then the potential ramp gets inverted.…”

Section: Resultsmentioning

confidence: 99%

Theoretical aspects of several successive two-step redox mechanisms in protein-film cyclic staircase voltammetry

Gulaboski

Kokoškarova

Mitrev

2012

Electrochimica Acta

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a b s t r a c tProtein-film voltammetry (PFV) is a versatile tool designed to provide insight into the enzymes physiological functions by studying the redox properties of various oxido-reductases with suitable voltammetric technique. The determination of the thermodynamic and kinetic parameters relevant to protein's physiological properties is achieved via methodologies established from theoretical considerations of various mechanisms in PFV. So far, the majority of the mathematical models in PFV have been developed for redox proteins undergoing a single-step electron transfer reactions. However, there are many oxido-reductases containing quinone moieties or polyvalent ions of transition metals like Mo, Mn, W, Fe or Co as redox centers, whose redox chemistry can be described only via mathematical models considering successive two-step electron transformation. In this work we consider theoretically the protein-film redox mechanisms of the EE (Electrochemical-Electrochemical), ECE (Electrochemical-Chemical-Electrochemical), and EECat (Electrochemical-Electrochemical-Catalytic) systems under conditions of cyclic staircase voltammetry. We also propose methodologies to determine the kinetics of electron transfer steps by all considered mechanisms. The experimentalists working with PFV can get large benefits from the simulated voltammograms given in this work.

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“…5,15 Mathematical models were developed by hypothesizing several surface species and their rates for formation and reduction. 5,[16][17][18] The effect of parameters in the models on voltammograms was discussed, or the models were validated by appropriate selection of parameters that reproduce experimental voltammograms. Even by the latest model, however, some features in the cyclic voltammograms (CVs) and oxide growth rate are still not well reproduced.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Oxide Formation and Reduction at Pt Catalyst in Polymer Electrolyte Fuel Cells

Suzuki

Morimoto

2016

Electrochemistry

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The rates of oxide formation and reduction at platinum catalyst in polymer electrolyte fuel cells were measured potentiostatically with various potential histories to reveal the kinetics of the reactions. Reaction rates during potential holds after an anodic or a cathodic sweep were examined as a function of potential and PtOH-equivalent oxide coverage. At 500 and 600 mV vs. RHE, the oxide coverage increased or decreased with increasing time depending on the potential history; this result indicates that the surfaces with different potential histories have different surface states. Oxide reduction rates were compared by changing potential and duration for oxide formation to attain the same coverage before the reduction. Oxide formed at a higher potential for a shorter period of time was easier to reduce than oxide formed at a lower potential for a longer period of time. This indicates that the oxide-formation potential and/or oxide-formation time are factors to determine the oxide reduction rate.

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Theory of Successive Electron Transfer Steps in Cyclic Voltammetry: Application to Oxygen Pseudocapacitance on Platinum

Cited by 59 publications

References 8 publications

Kinetics of Aging of the Oxygen Monolayer on Platinum under a Complex Potentiodynamic Perturbation Program

Kinetics of Aging of the Oxygen Monolayer on Platinum under a Complex Potentiodynamic Perturbation Program

Theoretical aspects of several successive two-step redox mechanisms in protein-film cyclic staircase voltammetry

Kinetics of Oxide Formation and Reduction at Pt Catalyst in Polymer Electrolyte Fuel Cells

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