Charge transport in electroactive polymers consisting of fixed molecular redox sites

Dalton, E. F.; Surridge, Nigel A.; Jernigan, J. C.; Wilbourn, Keith O.; Facci, John S.; Murray, Royce W.

doi:10.1016/0301-0104(90)80026-t

Cited by 160 publications

(171 citation statements)

References 73 publications

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“…Similar quasi-diffusive effects have been discussed for a number of electroactive polymer systems. 205,[242][243][244][245][246] In light of the above discussion, the rate of charge percolation in the oxide layers may be quantified in terms of a charge transport diffusion coefficient D CT , reflecting either the rate of electron 'hopping' or the diffusion of protons/hydroxide ions via a rapid Grotthus type mechanism. 17 In this sense, Laviron [247][248][249][250][251][252] and Aoki 253,254 have developed useful models allowing the voltammetric response to be analysed quantitatively as a function of sweep rate.…”

Section: Charge Transport In Transition Metal Oxidesmentioning

confidence: 99%

Redox and electrochemical water splitting catalytic properties of hydrated metal oxide modified electrodes

Doyle

Godwin

Brandon

et al. 2013

Phys. Chem. Chem. Phys.

537

565

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This paper presents a review of the redox and electrocatalytic properties of transition metal oxide electrodes, paying particular attention to the oxygen evolution reaction. Metal oxide materials may be prepared using a variety of methods, resulting in a diverse range of redox and electrocatalytic properties. Here we describe the most common synthetic routes and the important factors relevant to their preparation. The redox and electrocatalytic properties of the resulting oxide layers are ascribed to the presence of extended networks of hydrated surface bound oxymetal complexes termed surfaquo groups. This interpretation presents a possible unifying concept in water oxidation catalysis -bridging the fields of heterogeneous electrocatalysis and homogeneous molecular catalysis. In contextOver the past 50 years considerable research efforts have been devoted to the realisation of efficient, economical and renewable energy sources. Metal oxide materials have played a large part in this drive with demonstrated applications at both the research and commercial level. Their use in areas such as batteries, fuel cells and water electrolysis has resulted in the development of materials with a diverse range of structural and chemical properties. In all cases, understanding the fundamental electrochemistry of the material can be invaluable for rational design and optimisation. This review focuses on the redox, charge transport and electrocatalytic properties of transition metal oxide electrodes as they pertain to the electrolytic splitting of water. Particular emphasis is placed on the nature of the active surface which is interpreted in terms of hydrated interlinked oxymetal complexes termed surfaquo groups. In this way, the review seeks to bridge the gap between heterogeneous electrocatalysis and homogeneous molecular catalysis for water oxidation, areas of considerable modern interest and activity.

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Section: Charge Transport In Transition Metal Oxidesmentioning

confidence: 99%

Redox and electrochemical water splitting catalytic properties of hydrated metal oxide modified electrodes

Doyle

Godwin

Brandon

et al. 2013

Phys. Chem. Chem. Phys.

537

565

View full text Add to dashboard Cite

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“…The variation of the hydrous oxide charge capacity, Q (which is proportional to the redox charge capacity, C, defined for electroactive polymer films in the work of Chidsey and Murray, [28][29][30][31] ) with analytical sweep rate is outlined in Fig. 6.…”

Section: Analysis Of the Redox Switching Reaction In The Hydrous Layermentioning

confidence: 99%

Redox switching and oxygen evolution electrocatalysis in polymeric iron oxyhydroxide films

Lyons

Brandon

2009

Phys. Chem. Chem. Phys.

101

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Outstanding issues regarding the redox switching characteristics and the oxygen evolution reaction (OER) electrocatalytic behaviour of multicycled iron oxyhydroxide films in aqueous alkaline solution have been examined. Charge percolation through the hydrous layer has been quantified, using cyclic voltammetry, in terms of a charge transport diffusion coefficient D CT which admits a value of ca. 3 Â 10 À10 cm 2 s À1 . Steady-state Tafel plot analysis and electrochemical impedance spectroscopy have been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slope values of ca. 60 mV dec À1 and ca. 120 mV dec À1 are found at low and high overpotentials respectively, whereas the reaction order with respect to hydroxide ion activity changes from ca. 3/2 to ca. 1 as the potential is increased. These observations are rationalised in terms of a kinetic scheme involving Temkin adsorption and the rate determining formation of a physisorbed hydrogen peroxide intermediate on the oxide surface. The dual Tafel slope behaviour is ascribed to the potential dependence of the surface coverage of adsorbed intermediates.

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“…Since we deal with a porous system with relatively large surface area, physical Fickian diffusion of redox probes is obviously one option. Electron hopping, which involves charge transfer between fixed redox sites in the film is also feasible and dominates under high concentrations of redox sites and fast self-exchange electron transfer [58,59]. The third mechanism occurs when mobile counter-ions that are capable of providing charge balance during electron transfer are present in the host matrix and control charge transfer.…”

Section: Factors Affecting Diffusion and Effective Concentrationmentioning

confidence: 99%

Application of Sol‐Gel Technology for Electroanalytical Sensing

et al. 2003

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The applicability of thin sol-gel films as selective interfaces in electrochemical sensors has been examined. This requires not only to create a selective interface but also to enable facile diffusion of the analytes across the films. Creation of selectivity has been aimed by molecularly imprinting an electroactive species in the course of sol-gel formation. We have focused primarily on imprinting an iron(II) complex, i.e., tris(2,2'-bipyridine)iron(II) (Fe(bpy) 2 3 , as a means of selectively determining iron(II) in aqueous solution. Hence, the effect of different parameters, such as the composition of the sol-gel film and the hydrolysis and drying time, on the diffusion of Fe(bpy) 2 3 , has been studied. We find that diffusion can be remarkably enhanced upon adding polyethylene glycol or a surfactant, such as decanoic acid. Nevertheless, so far we have not been able to develop thin films, which exhibit selectivity towards this inorganic species. The difficulties in designing such selective interfaces for heavy metals as opposed to organic species is demonstrated by successfully applying the same approach for designing a selective interface for diethyl-p-nitrophenyl phosphate (paraoxon).

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Charge transport in electroactive polymers consisting of fixed molecular redox sites

Cited by 160 publications

References 73 publications

Redox and electrochemical water splitting catalytic properties of hydrated metal oxide modified electrodes

Redox and electrochemical water splitting catalytic properties of hydrated metal oxide modified electrodes

Redox switching and oxygen evolution electrocatalysis in polymeric iron oxyhydroxide films

Application of Sol‐Gel Technology for Electroanalytical Sensing

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