Electrochemical Impedance Spectroscopy of Polyelectrolyte Multilayer Modified Electrodes

Barreira, Sérgio V. P.; Garcı́a-Morales, Vladimir; Pereira, Carlos M.; Manzanares, José A.; Silva, A. Fernando

doi:10.1021/jp0466845

Cited by 91 publications

(140 citation statements)

References 57 publications

Supporting

Mentioning

125

Contrasting

Unclassified

Order By: Relevance

“…5. According to PBE model [40,41,[50][51][52], the diffusion impedance is determined by the Warburg coefficient σ and coverage of the blocking layer, θ. The active area of microelectrode is represented as 1−θ.…”

Section: Resultsmentioning

confidence: 99%

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Szroeder¹,

Tsierkezos

Walczyk³

et al. 2014

J Solid State Electrochem

View full text Add to dashboard Cite

Electrocatalytic activity of graphene grown epitaxially on SiC is studied using cyclic voltammetry and electrochemical impedance spectroscopy. AFM images show steplike topography of SiC-graphene. For ferri-/ferrocyanide redox couple, no voltammetric response is observed at the pristine graphene. Basal planes of graphite are electrochemically inactive as well. After electrochemical oxidation, apparent redox peaks appear at both the graphene and graphite electrode. However, more intensive redox peaks are observed at graphene, where simultaneous redox reaction with the adsorbed and the diffused ferri-/ferrocyanide ions occurs. Electrochemical impedance measurements show that the graphene electrode behaves like an array of microelectrodes. We used the partially blocked electrode model to fit impedance data. Using the fitting parameters, a size of microelectrodes was found to be 23.8±2.1 μm and the active surface of graphene was estimated to be 21 %. A value of the standard electron transfer rate constant found for the anodized epitaxial graphene (2.16±0.32)×10) is by one order of magnitude lower than the standard rate constant estimated for the anodized graphite basal planes (∼5 × 10 − 2 cm ⋅ s − 1 ).Electrochemical reduction causes total disappearance of electrochemical responses at the graphene electrode, whereas only slight decrease of the peak currents is observed at the reduced graphene. Such behavior proves that different activation mechanisms occur at the graphene and graphite electrodes.

show abstract

Section: Resultsmentioning

confidence: 99%

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Szroeder¹,

Tsierkezos

Walczyk³

et al. 2014

J Solid State Electrochem

View full text Add to dashboard Cite

show abstract

“…These CVs are similar to those observed in PEMUs. [18][19][20][21][22][23][24][25][26][27][28] As more layers are added, the peak current decreases and nonlinear slow diffusion begins to take place. A transition from peak-shaped to plateau-shaped voltammograms is then observed due to the increase of the charge-transfer resistance accompanying the gradual blocking of the electrode.…”

Section: Multilayer Characterizationmentioning

confidence: 99%

“…Charge transport through the multilayer was studied experimentally as well as theoretically by using two different redox pairs [Fe(CN) 6 ] 3-/4-and [Ru-(NH 3 ) 6 ] 3+/2+ . The theoretical model used is the capillary membrane model (CMM), which has been very recently developed to deal with charge transport through PEMUs, 27,28 and here its range of applicability is extended. Mass transport in this model accounts for the possible defects present in the multilayer leading to nonlinear diffusion.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

et al. 2005

Self Cite

View full text Add to dashboard Cite

Polyelectrolyte/gold nanoparticle multilayers composed of poly(L-lysine) (pLys) and mercaptosuccinic acid (MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized using UV-vis absorption spectroscopy, cyclic and square-wave voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. Charge transport through the multilayer was studied experimentally as well as theoretically by using two different redox pairs [Fe(CN) 6 ] 3-/4-and [Ru(NH 3 ) 6 ] 3+/2+ . This paper reports a large sensitivity to the charge of the outermost layer for the permeability of these assemblies to the probe ions. With the former redox pair, dramatic changes in the impedance response were obtained for thin multilayers each time a new layer was deposited. In the latter case, the multilayer behaves as a conductor exhibiting a strikingly lower impedance response, the electric current being enhanced as more layers are added for Au NP terminated multilayers. These results are interpreted quite satisfactorily by means of a capillary membrane model that encompasses the wide variety of behaviors observed. It is concluded that nonlinear slow diffusion through defects (pinholes) in the multilayer is the governing mechanism for the [Fe(CN) 6 ] 3-/4-species, whereas electron transfer through the Au NPs is the dominant mechanism in the case of the [Ru(NH 3 ) 6 ] 3+/2+ pair.

show abstract

“…Those multilayers were also more permeable to monovalent ions than multivalent ions, and the permeability of highly charged ions such as Fe(CN) 6 3− and Ru(NH 3 ) 6 3+ will decrease quickly when polyelectrolyte multilayers are assembled. 22 The slower diffusion with increased number of multilayer is attributed to the reduction of active area of charge transfer, and the active area may be merely a few spots on the film surface that are preferable to the transport of ions. 22 Farhat and Schlenoff used linear sweep voltammetry to study the transport of redox-active ferrocyanide and ferricyanide through heavily charged polyelectrolyte multilayers and explained the transfer of ions in the film as hopping between fixed "reluctant" ion exchange sites in the polyelectrolyte layers coming from the charge balance of the outermost polycations or polyanions.…”

mentioning

confidence: 99%

Kinetic Modulation of Pulsed Chronopotentiometric Polymeric Membrane Ion Sensors by Polyelectrolyte Multilayers

Shvarev

et al. 2007

Anal. Chem.

View full text Add to dashboard Cite

Polymeric membrane ion selective electrodes are normally interrogated by zero current potentiometry, and their selectivity is understood to be primarily dependent on an extraction/ionexchange equilibrium between the aqueous sample and polymeric membrane. If concentration gradients in the contacting diffusion layers are insubstantial, the membrane response is thought to be rather independent of kinetic processes such as surface blocking effects. In this work, the surface of calcium-selective polymeric ion-selective electrodes is coated with polyelectrolyte multilayers as evidenced by zeta potential measurements, atomic force microscopy and electrochemical impedance spectroscopy. Indeed, such multilayers have no effect on their potentiometric response if the membranes are formulated in a traditional manner, containing a lipophilic ion-exchanger and a calcium-selective ionophore. However, drastic changes in the potential response are observed if the membranes are operated in a recently introduced kinetic mode using pulsed chronopotentiometry. The results suggest that the assembled nanostructured multilayers drastically alter the kinetics of ion transport to the sensing membrane, making use of the effect that polyelectrolyte multilayers have different permeabilities toward ions with different valences. The results have implications to the design of chemically selective ion sensors since surface localized kinetic limitations can now be used as an additional dimension to tune the operational ion selectivity.Polymer membrane ion-selective electrodes are widely established for the reliable assessment of ion activities in complex samples and are indispensable tools in clinical analysis. Their ionselectivity is dictated by the thermodynamic ion-exchange selectivity of the polymer membrane. Recently, ion-selective membrane electrodes have started to be interrogated by pulsed chronopotentiometry. In this new technique, a discrete current pulse is imposed across an ion-selective membrane void of added ion-exchanger sites. The potential change associated with the resulting ion flux from the sample into the sensing phase can be monitored during or, at open circuit, immediately after the pulse before the membrane is regenerated under controlled potential conditions. At high sample concentrations the observed sensitivity (electrode slope) and selectivity normally agrees with that of the corresponding ion-selective electrodes interrogated at zero current. 1, 2 The imposed ion flux, however, depletes the analyte ions in the Nernst diffusion layer at a critical concentration, and very large (ca. 10-fold Nernstian) electrode slopes are observed in this concentration range. 3 The operational ion Ultra-thin films assembled from alternate adsorption of polycations and polyanions onto a charged substrate has attracted much attention in recent years due to their facile fabrication, high versatility and multi-functionality. The application of this technique has expanded into a number of areas, including biosensor surface modificat...

show abstract

Electrochemical Impedance Spectroscopy of Polyelectrolyte Multilayer Modified Electrodes

Cited by 91 publications

References 57 publications

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

Kinetic Modulation of Pulsed Chronopotentiometric Polymeric Membrane Ion Sensors by Polyelectrolyte Multilayers

Contact Info

Product

Resources

About