Showing papers on "Supporting electrolyte published in 2006"
TL;DR: An integrated approach to the control of deltaE(1/2) values, and therefore comproportionation equilibria, through medium effects was delineated for multi-step redox reactions involving cationic products.
Abstract: An integrated approach to the control of ΔE1/2 values, and therefore comproportionation equilibria, through medium effects was delineated for multi-step redox reactions involving cationic products. ΔE1/2 values (defined as E1/22+/1+ − E1/21+/0) of the two one-electron oxidations of bis(fulvalene)dinickel, 1, were measured under 45 different conditions of solvent and supporting electrolyte. The smallest value, 212 mV, was found in anisole/0.1 M [NBu4]Cl and the largest, 850 mV, in CH2Cl2/0.02 M Na[B(C6H3(CF3)2)4]. By systematically changing the solvent properties, the degree of ion-pairing strengths of the supporting electrolyte ions, and the concentration of the electrolytes, a set of ideal properties was found for maximizing ΔE1/2 values involving positively charged electrode products. Most importantly (i) the solvent must be of lower polarity and low donor strength and (ii) the supporting electrolyte must have a weakly coordinating anion (WCA). The contrast in ion-pairing tendencies of 12+ with WCAs (on...
449 citations
TL;DR: It can be concluded in general that the triazine containing higher molecular weight diazo compounds takes more time for complete de-colorization than the mono azo or anthraquinone containing dye compounds.
326 citations
TL;DR: Electrochemical oxidation of phenol was carried out in a parallel plate reactor using ruthenium mixed metal oxide electrode and the effects of initial pH, temperature, supporting electrolyte concentration, current density, flow rate and initial phenol concentration on the removal efficiency were investigated.
198 citations
TL;DR: The interior surface of the glass nanopore electrode was modified with spiropyran moieties to impart photochemical control of molecular transport through the pore orifice, allowing photoselective transport of redox molecules to the electrode surface based on charge discrimination.
Abstract: The interior surface of the glass nanopore electrode was modified with spiropyran moieties to impart photochemical control of molecular transport through the pore orifice (15−90 nm radius). In low ionic strength acetonitrile solutions, diffusion of a positively charged species (Fe(bpy)32+) is electrostatically blocked with ∼100% efficiency by UV light-induced conversion of the neutral surface-bound spiropyran to its protonated merocyanine form (MEH+). Transport through the pore orifice is restored by either irradiation of the electrode with visible light to convert MEH+ back to spiropyran or addition of a sufficient quantity of supporting electrolyte to screen the electrostatic field associated with MEH+. The transport of neutral redox species through spiropyran-modified glass nanopores is not affected by light, allowing photoselective transport of redox molecules to the electrode surface based on charge discrimination. The glass nanopore electrode can also be employed as a photochemical trap, by UV light...
173 citations
TL;DR: The use of a trifluorotris(pentafluoroethyl)phosphate-based ionic liquid, specifically, as supporting electrolyte in acetonitrile solutions affords a wider anodic window, which is attributed to the high stability of the anionic component of these intrinsically conductive and thermally robust compounds.
Abstract: The electrochemical windows of acetonitrile solutions doped with 0.1 M concentrations of several ionic liquids were examined by cyclic voltammetry at gold and platinum microelectrodes. These results were compared with those observed in the commonly used 0.1 M tetrabutylammonium perchlorate/acetonitrile system as well as with neat ionic liquids. The use of a trifluorotris(pentafluoroethyl)phosphate-based ionic liquid, specifically, as supporting electrolyte in acetonitrile solutions affords a wider anodic window, which is attributed to the high stability of the anionic component of these intrinsically conductive and thermally robust compounds.
156 citations
TL;DR: Variation of the NaCl concentration demonstrated that, although only low concentrations ofNaCl are necessary to result in the complete removal of atrazine in solution, TOC removal is almost linearly dependent on the quantity of NaCl in solution.
137 citations
TL;DR: In this paper, the Taguchi method was used to determine the optimum conditions for the phosphate removal from wastewater by electrocoagulation with aluminum plate electrodes, and the experimental parameters investigated were initial phosphate concentration, initial pH of the wastewater, supporting electrolyte concentration, support electrolyte type and current density.
121 citations
TL;DR: In this article, the borohydride ion is oxidised on the gold electrode with an electrochemical rate constant of around 1 cm−s−1 at intermediate potentials where side reactions had less effect.
111 citations
TL;DR: The results demonstrate the participation of partially oxidised Cl- species at the electrode surface, which act as an intermediate in the electron transfer between the pesticide molecule and the electrode, suggesting enhanced activity in the presence of NaCl.
99 citations
TL;DR: Metal (Pt, stainless steel) coated with partially oxidized polypyrrole with good stability over a period of 1 day and relatively reproducible potential in a given solvent and supporting electrolyte is presented.
Abstract: As an alternative to the usual commercial reference and quasi-reference electrodes (QREs), we propose metal (Pt, stainless steel) coated with partially oxidized polypyrrole as a QRE. The electrode is easily fabricated by cyclic voltammetry (CV) with the metal electrode in an acetonitrile or CH2Cl2 solution of 10 mM pyrrole containing 0.1 M Bu4NPF6. These QREs were more stable than the widely used metal (e.g., Ag, Pt) wire QRE as demonstrated by testing in several aqueous and organic media, with the stability checked by CV with ferrocenemethanol as the redox species. The results obtained demonstrate good stability of these QREs over a period of 1 day and relatively reproducible potential in a given solvent and supporting electrolyte. This electrode has the advantage that it does not contaminate the test solution with ions or solvent from a usual liquid electrolyte (e.g., the KCl in an Ag/AgCl). It is also simple to fabricate very small electrodes for use in nanocells, e.g., in scanning tunneling and electrochemical microscopy.
95 citations
TL;DR: In this paper, the effects of temperature, concentration of borohydride and supporting electrolyte and oxidant conditions on the performance of direct BORHYDE fuel cell are reported.
TL;DR: The structure of poly(acrylic acid) (PAA) molecules in electrolyte solutions obtained from molecular dynamic simulations was compared with experimental data derived from dynamic light scattering (PCS), dynamic viscosity, and electrophoretic measurements, which found that the experimental results were in a good agreement with the Brenner's viscosities theory for prolate spheroid suspensions.
Abstract: In this work, the structure of poly(acrylic acid) (PAA) molecules in electrolyte solutions obtained from molecular dynamic simulations was compared with experimental data derived from dynamic light scattering (PCS), dynamic viscosity, and electrophoretic measurements. Simulations and measurements were carried out for polymer having a molecular weight of 12 kD for various ionic strengths of the supporting electrolyte (NaCl). The effect of the ionization degree of the polymer, regulated by the change in the pH of the solution in the range 4−9 units, was also studied systematically. It was predicted from theoretical simulations that, for low electrolyte concentration (10-3 M) and pH = 9 (full nominal ionization of PAA), the molecule assumed the shape of a flexible rod having the effective length Lef = 21 nm, compared to the contour length Lext = 41 nm predicted for a fully extended polymer chain. For an electrolyte concentration of 0.15 M, it was predicted that Lef = 10.5 nm. For a lower ionization degree, a...
TL;DR: In this article, a chalcopyrite-based thin film was grown by one-step cathodic electrodeposition on Pt-coated glass using amperometry mode (fixed potential), in a three-electrode potentiostatic system containing the precursor solutions, 10mM CuSO 4, 50mM InSO 4, 30mM SeO 2, and 0.1m K 2 SO 4 as a supporting electrolyte, at a pH of 1.5 (±0.1).
Patent•
19 Jun 2006
TL;DR: A vanadium redox cell having a positive half cell containing a negative half cell solution comprising a supporting electrolyte selected from H2SO4, HBr and HBr/HCl mixtures and one or more vanadium ions selected from the group vanadium (EI), Vanadium(IV), vanadium(V), Br3 and Br2Cl is defined in this paper.
Abstract: A vanadium redox cell having a positive half cell containing a positive half cell solution comprising a supporting electrolyte selected from H2SO4, HBr/HCl mixtures and one or more ions selected from the group vanadium (EI), Vanadium(IV), Vanadium (V), Br3 and Br2Cl; a negative half cell containing a negative half cell solution comprising a supporting electrolyte selected from H2SO4, HBr and HBr/HCl mixtures and one or more vanadium ions selected from the group Vanadium (II), Vanadium (III) and Vanadium (FV) and a perfluorinated cast cation exchange membrane or separator disposed between the positive and negative half cells and in contact with the positive and negative half cell solutions.
TL;DR: In this article, a carbon paste electrode modified with zirconium phosphated-silica was used for the determination of cadmium, which demonstrated linear response over a wide range of Cd(II) concentration with an accumulation time of 120 s. The effects of potential interfering ions were studied, and it was found that the proposed procedure was free from most interferences.
Abstract: A carbon paste electrode modified with zirconium phosphated-silica was used for the determination of cadmium. The measurements were carried out in three steps including an open circuit accumulation, subsequent electrolysis of accumulated cadmium at the carbon paste electrode, and differential pulse voltammetric determination. The effects of several experimental variables such as carbon paste composition, pH of solution at the accumulation step, pH and concentration of supporting electrolyte, electrolysis potential, accumulation time and electrolysis time were studied. The resulting electrode demonstrated linear response over a wide range of Cd(II) concentration (3–1400 ng mL −1 ) with an accumulation time of 120 s. The effects of potential interfering ions were studied, and it was found that the proposed procedure was free from most interferences. The prepared electrode was used for determination of cadmium in some artificial synthetic samples, and very good recovery results were obtained over a wide concentration range of cadmium.
TL;DR: In divided flow-through cells, reductive electrolysis of Orange II (1) was first order in both substrate and applied current and gave the products of reductive cleavage at the azo linkage in essentially quantitative yield.
Abstract: In divided flow-through cells, reductive electrolysis of Orange II (1) was first order in both substrate and applied current and gave the products of reductive cleavage at the azo linkage in essentially quantitative yield. Oxidative electrolysis was also pseudo-first-order and led to mineralization. At a boron-doped diamond anode, the rate of disappearance of 1 closely tracked the loss of total organic carbon from solution. In undivided cells oxidation and reduction occurred simultaneously; under acidic conditions the reduction products (anilines) were rather persistent because they were present as ammonium ions, but under alkaline conditions the anilines were mineralized along with the starting material. When chloride ion was present in the supporting electrolyte, electrochemical oxidation afforded hypochlorite, and the disappearance of 1 proceeded by way of hypochlorination.
TL;DR: In this article, a polypyrrole (Ppy) film containing nanometer-sized platinum and Pt/Pd bimetallic particles is electro-synthesized on ITO glass plates by voltammetric cycling between −0.1 and +1
TL;DR: In this paper, homopolymerization of 3-chlorothiophene and copolymerization with 3-methylthiophene (MeT) were carried out via potentiodynamic and galvanostat methods by using ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM]PF 6 ) as the growth medium and the supporting electrolyte.
TL;DR: The influence of pH and ionic strength on permselective transport in nanoporous opal films prepared from 440 nm silica spheres was investigated by cyclic voltammetry in aqueous and acetonitrile solutions.
Abstract: The influence of pH and ionic strength on permselective transport in nanoporous opal films prepared from 440 nm silica spheres was investigated by cyclic voltammetry in aqueous and acetonitrile solutions. Three-layer opal films were deposited from a 1.5 wt % colloidal solution of silica spheres onto 25-μm-diameter Pt microdisk electrodes shrouded in glass. The films were chemically modified by immersing them in a dry acetonitrile solution of 3-aminopropyl triethoxysilane. When the surface amino groups of the modified opal films are protonated and there is little or no supporting electrolyte present in solution, the flux of cationic redox species through the opal membrane is blocked because of electrostatic repulsion. The permselectivity is pH-dependent and can be modulated by adjusting the Debye screening length within the nanopores of the opal by changing the ionic strength of the contacting solution.
TL;DR: The steady-state voltammetric behavior of truncated conical nanopore electrodes (20-200 nm orifice radii) is investigated in low ionic strength solutions and the dependence of the limiting current on the relative concentrations of the supporting electrolyte and redox molecule is accurately predicted by theory previously developed for microdisk electrodes.
Abstract: The steady-state voltammetric behavior of truncated conical nanopore electrodes (20−200 nm orifice radii) has been investigated in low ionic strength solutions. Voltammetric currents at the nanopore electrode reflect both diffusive and migrational fluxes of the redox molecule and, thus, are strongly dependent on the charge of the redox molecule and the relative concentrations of the supporting electrolyte and redox molecule. In acetonitrile solutions, the limiting current for the oxidation of the positively charged ferrocenylmethyltrimethylammonium ion is suppressed at low supporting electrolyte concentrations, while the limiting current for the oxidation of the neutral species ferrocene is unaffected by the ionic strength. The dependence of the limiting current on the relative concentrations of the supporting electrolyte and redox molecule is accurately predicted by theory previously developed for microdisk electrodes. Anomalous values of the voltammetric half-wave potential observed at very small nanopo...
Patent•
08 Jun 2006
TL;DR: In this paper, a nonaqueous electrolyte battery comprising a positive electrode, a negative electrode, an electrolyte comprising the organic solvent in which a supporting electrolyte is dissolved, a separator, a sealing gasket, a positive electrodes can, and a negative electrodes can is provided between the negative electrode can and the positive electrode can.
Abstract: PROBLEM TO BE SOLVED: To provide a highly reliable nonaqueous electrolyte battery capable of preventing battery performance degradation due to the leakage of moisture to the inside of the battery during storage in a high-temperature and humidity environment SOLUTION: In the nonaqueous electrolyte battery comprising a positive electrode, a negative electrode, an electrolyte comprising the organic solvent in which a supporting electrolyte is dissolved, a separator, a sealing gasket, a positive electrode can, and a negative electrode can, the sealing gasket is provided between the negative electrode can and the positive electrode can, and the sealing gasket is PFA or ETFE COPYRIGHT: (C)2006,JPO&NCIPI
TL;DR: Results indicate that the electrochemical method can be used to treat dye house effluents and the influence of effluent initial concentration, pH, supporting electrolyte and the electrode material on rate of degradation has been critically examined.
TL;DR: In this paper, copolymerization of o-anisidine and o-toluidine was achieved electrochemically in aqueous solution containing H2SO4 as supporting electrolyte.
TL;DR: Barriere et al. as mentioned in this paper studied the anodic oxidations of three compounds having two Rh-containing moieties linked by a fulvalendiyl (Fv) dianion in varying electrolyte media.
TL;DR: In this paper, the Pt nanoparticles were deposited at the surface of well-aligned multi-walled carbon nanotubes (MWNTs) by potential cycling between +0.50 and −0.70 V at a scanning rate of 50 mV · s−1 in 5 mM Na2PtCl6 solution containing 0.1 M NaCl.
Abstract: Platinum (Pt) nanoparticles were deposited at the surface of well-aligned multi-walled carbon nanotubes (MWNTs) by potential cycling between +0.50 and −0.70 V at a scanning rate of 50 mV · s−1 in 5 mM Na2PtCl6 solution containing 0.1 M NaCl. The electrocatalytic oxidation of methanol at the nanocomposites of Pt nanoparticles/nanotubes (Ptnano/MWNTs) has been investigated using 0.2 M H2SO4 as supporting electrolyte. The effects of various parameters, such as Pt loading, concentration of methanol, medium temperature as well as the stability of Ptnano/MWNTs electrode, have been studied. Compared to glassy carbon electrode, carbon nanotube electrode significantly enhances the catalytic efficiency of Pt nanoparticles for methanol oxidation. This improvement in performance is due not only to the high surface area and the fast electron transfer rate of nanotubes but also to the highly dispersed Pt nanoparticles as electrocatalysts at the tips and the sidewalls of nanotubes.
TL;DR: Under optimal conditions good voltammetric responses were obtained by means of square wave anodic stripping voltammetry in unstirred analyte solutions of 5 x 10(-8) to 10(-6)M, even in the absence of added buffer.
TL;DR: In this paper, the characterization of polycarbazole thin films formed on micron sized carbon fiber electrodes was performed by electrochemical methods (i.e., cyclic voltammetric measurements, solid state conductivity measurements (four point probe), spectrophotometric methods (ultraviolet/visible spectroscopy (UV-vis), ex situ spectroelectrochemistry, fourier transform infrared reflectance spectroscope (FTIR-ATR)) and scanning electron microscopy (SEM).
Abstract: Carbazole was electrochemically synthesized on carbon fiber microelectrodes (CFMEs) in different electrolyte and solvent media. The characterization of polycarbazole thin films formed on micron sized carbon fiber electrodes was performed by electrochemical methods (i.e., cyclic voltammetric measurements, solid state conductivity measurements (four point probe), spectrophotometric methods (ultraviolet/visible spectroscopy (UV–vis), ex situ spectroelectrochemistry, fourier transform infrared reflectance spectroscopy (FTIR-ATR)) and scanning electron microscopy (SEM). The best electrolyte and solvent in regards to yield, conductivity and charge for the electro-grafting was sodium perchlorate in acetonitrile, whose conductivity was 3.60 mS cm−1, had a yield of 89% and had a charge of 5.50C. The effects of scan rate, feed ratio, supporting electrolyte and solvent type on the electropolymerization are discussed.
TL;DR: Fabrication and application of a voltammetric sensor based on gold 2-mercaptobenzothiazole self-assembled monolayer (Au-MBT SAM) for determination of silver ion and the effect of potential interfering ions on the determination of Ag(I) was studied.
TL;DR: The morphological aspects of poly(N-vinyl carbazole) (PVC)-functionalized CNTs are revealed by transmission electron microscopy (TEM) studies, and high specific discharge capacity is reported for PVC-functionalized single- and multi-walled carbon nanotubes, respectively.
Abstract: Electrochemical polymerization of N-vinyl carbazole (VC) on carbon nanotube (CNT) films was studied by cyclic voltammetry (CV) in LiClO4/acetonitrile solutions. Comparing the cyclic voltammograms recorded on a blank Pt electrode with those obtained when single- or multi-walled carbon nanotube (SWNT or MWNT) films were previously deposited onto the Pt electrode, a downshift of the VC reduction peak potential is observed in the latter case. The influences of monomer concentration, type of solvent, and supporting electrolyte on the polymerization conditions and electrochemical properties of these composite materials are also investigated. The morphological aspects of poly(N-vinyl carbazole) (PVC)-functionalized CNTs are revealed by transmission electron microscopy (TEM) studies. A covalent functionalization of carbon nanotubes with PVC is invoked as a result of attenuated total reflection infrared (ATR-IR) spectroscopic studies. Using PVC-functionalized CNTs as a positive electrode and an electrolytic solution containing LiPF6, the charge-discharge characteristics of the rechargeable lithium cells are determined. High specific discharge capacity (approximately 45 and 115 mA h g(-1)) is reported for PVC-functionalized single- and multi-walled carbon nanotubes, respectively.
TL;DR: In this paper, the ability of the ionic liquid trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate (aph4.cph12) to act as an ionic conductor in toluene has been investigated at platinum and glassy carbon macrodisc electrodes.