Search results for "Electrode"
showing 10 items of 950 documents
Electrochemical impedance spectroscopy as a tool to estimate thickness in PB films
2006
The analysis of the faradaic impedance of electroactive films provides a characteristic point from which it is possible to estimate the thickness of thin films. Thus, electrochemical impedance spectroscopy was used in this paper as a fast and easy technique to estimate this thickness. The proposed method was checked on PB films. Keywords: Prussian blue, Electrochemical impedance spectroscopy, Thickness
Prussian blue films deposited on graphite+epoxy composite electrodes: electrochemical detection of the second percolation threshold
2000
Abstract The electrochemical behavior of Prussian blue films galvanostatically electrodeposited on graphite+epoxy-resin composite electrodes was studied. The composite electrodes were prepared with different graphite proportions and their effect on electrochemical reduction of the Prussian blue was analyzed by means of the uncompensated resistance approximation and the electrical percolation theory. The results suggest that the electrode with 60% graphite reaches the second percolation threshold and its internal structure changes from a compact to a porous one. Mechanical tensile tests were performed in order to confirm the critical behavior of this material at the percolation thresholds. T…
Ohmic drop of Prussian-blue/graphite+epoxy electrodes
1999
Abstract Ohmic drop effects on the voltammogram shape of the Prussian-blue⇌Everitt’s salt system have been studied by considering the electroactive film model. As the uncompensated resistance varies, the experimental characteristic curve parameters also varies. A dependence of the voltammograms with the graphite proportion was found related with the ohmic drop due to the composite electrodes. The optimal graphite proportion to obtain a good faradaic-to-charge current ratio was 62% in weight which coincides with the second percolation threshold. The ohmic overpotential, which relates the ohmic drop with the electrochemical magnitudes, is also minimum at this proportion.
One-stage periodical anodic-cathodic double pulse deposition of nanocomposite materials. Application to Prussian Blue/polypyrrole film coated electro…
2014
Abstract Novel electrochemical method of one-stage deposition of composite films on electrode surface has been proposed. The procedure includes a periodical series of potentiostatic or galvanostatic pulses of alternative polarity imposed at electrode in contact with a mixture of two solute precursors, one of which is able to generate a solid phase under its electrooxidation while another one is transformed into another solid phase under its electroreduction. Parameters of anodic and cathodic pulses (potential or current, pulse duration) may be chosen independently from one another, their relation allows one to vary the relative contents of components in the deposited composite. Thickness of…
Chronoamperometry of prussian blue films on ITO electrodes: Ohmic drop and film thickness effect
1999
Abstract The chronoamperograms associated with the reduction of prussian blue films deposited onto indium tin oxide (ITO) electrodes to the Everitt’s salt form, are influenced by the ohmic drop effect. These chronoamperometric curves have been simulated by means of a numerical finite difference model which is able to explain their shape and their dependence on the thickness of the film and on the uncompensated resistance. An analytical expression which describes the dependence of current against time at initial times considering the ohmic drop effect has also been proved when applied to these chronoamperometric curves at short times.
A numerical approach to the voltammograms of the reduction of Prussian Blue films on ITO electrodes
1997
The uncompensated resistance, mainly due to the ITO electrode, modifies the shape of voltammetric curves of the system Prussian Blue ⇄ Everitt's Salt films deposited on this transparent electrode. A numerical finite difference model which is able to explain the shape of these voltammetric curves is studied in this paper. This model explains the dependence of voltammetric curves on the film thickness and uncompensated resistance.
Correction of mass drift in ac-electrogravimetry of Prussian Yellow films. Mass impedance under apparently non-steady state condition
2014
Abstract Mass impedance spectroscopy allows the modulated response of mass of a resonant electrode to be followed at different perturbation frequencies during electrochemical impedance spectroscopy experiments (ac-electrogravimetry). However, some difficulties appear if a continuous mass change takes place foreign to the mass changes due to the ac-modulated electrochemical processes. A new strategy is proposed to solve this limitation. Both, mass and potential analog signals are recorded frequency by frequency from 100 Hz up to the lowest frequencies. Then, a numerical procedure based on a multiparametric fitting of raw data against the elapsed time allows the contribution due to the modula…
Modeling and numerical simulation of the propagation of pitting corrosion of iron in chlorinated medium : contribution to the evaluation of the durab…
2012
This study deals with the understanding of the mechanisms of pitting corrosion susceptible to occur on carbon steel selected for high level nuclear waste containers. Transport/reaction models have been developed in order to simulate, by finite element method, the propagation of a pit on iron in chlorinated medium. For conservative models, pit is activated by imposing a potential on metal. Thanks to different parametric studies (geometry, environment…) simulations have permitted to classify, by severity order, the factors responsible of the increase or the inhibition of the localized corrosion rate. Otherwise, experiments on occluded (called « lead-in-pencil ») electrodes confirm that confin…
Low-energy epicardial pacing in children: the benefit of autocapture.
1999
Abstract Background . Permanent cardiac pacing in children results commonly in augmented energy consumption because of the high pacing rates and the ample stimulation safety margin applied in children. Cardiovascular anatomy and limited venous access sometimes preclude the otherwise preferred endocardial approach. In this multicenter patient series, we studied the feasibility, safety, and energy saving obtained by a combination of steroid-eluting epicardial leads with autocapture devices capable of ongoing adjustment of the stimulation output to the prevailing threshold. Methods . Autocapture devices (Pacesetter Microny SR+ and Regency SR+; Pacesetter, Solna, Sweden) and steroid-eluting epi…
Optimizing charge breeding techniques for ISOL facilities in Europe: conclusions from the EMILIE project
2015
ThuM07; International audience; The present paper summarizes the results obtained from the past few years in the framework ofthe Enhanced Multi-Ionization of short-Lived Isotopes for Eurisol (EMILIE) project. The EMILIEproject aims at improving the charge breeding techniques with both Electron Cyclotron ResonanceIon Sources (ECRIS) and Electron Beam Ion Sources (EBISs) for European Radioactive Ion Beam(RIB) facilities. Within EMILIE, an original technique for debunching the beam from EBIS chargebreeders is being developed, for making an optimal use of the capabilities of CW post-acceleratorsof the future facilities. Such a debunching technique should eventually resolve duty cycle andtime st…