Search results for " Electrode"

Flow-through voltammetry (FTV) with the hanging mercury drop electrode (HMDE)

1995

A flow-through cell with integrated hanging mercury drop electrode for voltammetric, inverse voltammetric, adsorptive voltammetric, and chronoamperometric methods is described. HMDE droplets are automatically formed and renewed. By optimizing the flow-channel the sensitivity could be increased approximately five times in comparison with batch methods using the same deposition conditions.

Solvent-Independent Electrode Potentials of Solids Undergoing Insertion Electrochemical Reactions: Part I. Theory

2012

A formally solvent-independent redox system can be theoretically defined using the Lovric and Scholz modeling of the voltammetry of microparticles for ion-insertion solids. The proposed theory is based on the extra-thermodynamic assumptions that no net charge accumulates at the solid|electrolyte interface and the assumption that the structure of the solid and the ion binding remain unaffected by the solvent. Under voltammetric conditions, the corresponding redox potential can be estimated from voltammetric and chronoamperometric data assuming electrochemical reversibility and diffusive charge transport in the solution and solid phases, also taking into account ion partition (electrolyte/sol…

Tlenki lantanowców jako katalizatory elektrody tlenowej

2017

A microscale Kjeldahl nitrogen determination for environmental waters.

2008

A microscale Kjeldahl system has been designed which has been homemade reduced. The digestor unit of a macroKjeldahl system and a modified glassware microdistillation unit have been used. The optimal conditions for digestion and distillation have been established for ammonium and methylamine as model compound of organic amino nitrogen. The optimised procedure has been applied to the determination of Kjeldahl nitrogen in water samples. Recoveries near 100% and good precision have been achieved. This procedure combines nitrogen miniaturized system and the use of a selective ion electrode for ammonia detection. The analysis time was reduced 4.8 times and the analysis cost 6.6 times compared wi…

Measurement of the Md3+/Md2+ Reduction Potential Studied with Flow Electrolytic Chromatography

2013

The reduction behavior of mendelevium (Md) was studied using a flow electrolytic chromatography apparatus. By application of the appropriate potentials on the chromatography column, the more stable Md(3+) is reduced to Md(2+). The reduction potential of the Md(3+) + e(-) → Md(2+) couple was determined to be -0.16 ± 0.05 V versus a normal hydrogen electrode.

Electroplated Ni/Ni-Co multilayer coatings for higher corrosion-erosion resistance

2019

Erosion-corrosion behaviour of hierarchical structured hydrophobic nickel-cobalt coating, obtained by electrodeposition, was assessed. In situ electrochemical measurements were carried out to study the corrosion resistance and stability during erosion tests. The electrochemical behaviour was related to surface hydrophobicity and its hierarchical structure nature as well as its modification. The pure Ni showed the lowest erosion-corrosion resistance. A smoothing of the hierarchical structure and thus a reduction the hydrophobicity was highlighted. On the other hand, Ni-Co coating even if associated to a lower electrochemical stability showed a more stable hierarchical structure also at high …

Electrochemistry of TiO2–iron hexacyanocobaltate composite electrodes

2014

Abstract In this paper we investigate the electrochemical behavior of iron hexacyanocobaltate (FeHCC) in comparison to the cobalt hexacyanoferrate (CoHCF). The best results were achieved on electrochemical synthesized film of FeHCC on the TiO2 modified electrodes. The chemical and physical characterizations confirm the formation of the FeHCC with the classical cubic crystal structure of the Prussian blue analogs, with cell parameter a very close to 10 A, as well as the formation of micro aggregates of TiO2 covered by FeHCC. The synthesis was performed on various substrates such as glassy carbon (GC), graphite foil (GF) and indium tin oxide (ITO) in order to develop new technological applica…

Controlling the thermoelectric properties of polymers: application to PEDOT and polypyrrole

2015

Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films have been prepared by an electrochemical method in a three electrode cell. The films have been obtained at different oxidation levels regarded as bipolaron, polaron and neutral states by varying the voltage, as is usually done in conjugated heterocyclic polymers. The voltage (-0.2V1.0 V) has been applied versus a Ag/AgCl reference electrode, producing a variation of one order of magnitude in the electrical conductivity and the Seebeck coefficient of the films. In the voltage range explored, the electrical conductivity increases from 80 to 766 S cm(-1) in PEDOT and from 15 to 160 S cm(-1) in PPy, while the Seebeck coefficie…

A glassy carbon electrode modified by a triply-fused-like Co( ii ) polyporphine and its ability for sulphite oxidation and detection

2018

This article presents a Co(II) polyporphine conductive polymer easily and rapidly obtained (less than 2 h 30 min) on the surface of a glassy carbon electrode from the transformation of an initial Mg(II) porphine solution in a four-step process (including electrochemical and chemical stages). The intimate molecular structure is argued on the basis of the electrochemical response of the modified electrode, as well as its surface characterization. Owing to its apparent stability in water over potential cycling and its high density in active Co(II) centers, the electrosynthesized film shows its ability to catalyze sulphite oxidation in aqueous solutions. The mechanism of this molecular catalysi…

All-Solid-State Ag+-ISE Based on [2.2.2]p,p,p-Cyclophane

2001

All-solid-state ion-selective electrodes (ISEs) based on two ionophores with similar structure, i.e., [2.2.2] p,p,p-cyclophane and [2.2.2]m,p,p-cyclophane, were prepared and investigated. The ion-selective membranes were composed of the corresponding ionophore (1 %), potassium tetrakis(4-chlorophenyl)borate (0.5 %), 2-nitrophenyl octyl ether (65–66 %), and PVC (33 %). The ion-selective membrane was placed on top of a layer of the conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), working as ion-to-electron transducer. The resulting all-solid-state ISEs were conditioned in 0.01 M AgNO3 and investigated as Ag+-ISEs. The results show that [2.2.2] p,p,p-cyclophane is much more select…