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Showing papers on "Supporting electrolyte published in 2003"


Journal ArticleDOI
TL;DR: In this article, a vanadium chloride/polyhalide redox flow cell is described, which employs a polyhalide solution in the positive half-cell electrolyte and a V(II)/vanadium(III) chloride redox couple as the negative half-cells electrolyte.

251 citations


Journal ArticleDOI
TL;DR: In this paper, the anodic oxidation of 2-naphthol has been studied by cyclic voltammetry and chronoamperometry, using a range of electrode materials such as Ti-Ru-Sn ternary oxide, lead dioxide and boron-doped diamond (BDD) anodes.

164 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of the anion nature on electrochemical ozone production was analyzed in the light of the proposed electrode mechanism, revealing introduction into the electrolyte of anions having a high electronegativity changes the double layer structure resulting in an increase of surface concentration of the active centres leading to EOP.

137 citations


Journal ArticleDOI
TL;DR: In this paper, a polymer light-emitting electrochemical cells (LECs) were fabricated with MEH−PPV as the luminescent polymer and the ionic liquid of imidazolium salts as the supporting electrolyte.
Abstract: The polymer light-emitting electrochemical cells (LECs) were fabricated with MEH−PPV as the luminescent polymer and the ionic liquid of imidazolium salts as the supporting electrolyte. The imidazolium salts utilized include various 1-methyl-3-alkylimidazolium salts with the alkyl substituents of butyl (bmim), dodecyl (dmim), tetradecyl (tmim), or hexadecyl (hmim) and the anions of PF6- or BF4-, which possess different melting points from room temperature for [bmim+][PF6-] to 83 °C for [hmim+][PF6-]. The electroluminescent (EL) properties and the electronic structure of the LECs were characterized by current−voltage (I−V), light intensity−voltage (L−V), and ac impedance measurements. It was found that the phase compatibility between the conjugated polymer and the ionic liquid determines the performance of the light-emitting devices, and the concentration of the ionic liquid and the ionic conductivity of the polymer blend films also play an important role. The imidazolium salts investigated in this work are...

132 citations


Journal ArticleDOI
TL;DR: In this article, the authors analyzed the performance of parallel pathways during methanol oxidation at Pt(1.1/1) 1 and showed that the mechanism of the parallel pathway is sensitive to the nature of the supporting electrolyte.

118 citations


Journal ArticleDOI
Feng'en Chen1, Gaoquan Shi1, Mingxiao Fu1, Liangti Qu1, Xiaoyin Hong1 
TL;DR: In this paper, resonance Raman spectroscopic studies on as-grown thin polypyrrole (PPy) films electrochemically deposited on flat platinum electrode surfaces by direct oxidation of pyrrole in acetonitrile.

102 citations


Journal ArticleDOI
TL;DR: In this article, a modification of cytochrome c (cyt.c) by poly(ethylene oxide) (PEO) chains enabled the protein to be soluble in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid without denaturation.
Abstract: Modification of cytochrome c (cyt.c) by poly(ethylene oxide) (PEO) chains enabled the protein soluble in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid without denaturation. However, as the solution was full of ions, suitable supporting electrolyte (KCl) was essential for the electron transfer reaction of cyt.c in the ionic liquid to attain adequate ion size for the active center.

82 citations


Journal ArticleDOI
TL;DR: In this paper, the voltammetric responses of nickel hexacyanoferrate microstructures on electrodes are supported with the data of elemental analysis estimations obtained using atomic absorption and surface examination based on X-ray energy dispersive spectroscopy.

79 citations


Journal ArticleDOI
TL;DR: In this article, the results of the electrochemical degradation of cresols for wastewater treatment were performed in an electrochemical undivided cell reactor using a Ti/TiO2−RuO2+IrO2 anode.
Abstract: This paper presents the results of the electrochemical degradation of cresols for wastewater treatment. The experiments were performed in an electrochemical undivided cell reactor using a Ti/TiO2−RuO2−IrO2 anode. Preliminary experiments were conducted using sodium chloride and sodium sulfate as supporting electrolytes to study the effects on the removal of chemical oxygen demand (COD). Operating variables such as the initial pH, chloride concentration, initial cresol concentration, charge input, and current densities were studied using chloride as the supporting electrolyte for maximum degradation. The current efficiency and energy consumption during the degradation were calculated. The present investigation showed the formation of a higher concentration of adsorbable organic halides at the beginning of electrolysis, but this decreased to lower levels during prolonged electrolysis. The total organic carbon removal values were between 50 and 60% though maximum COD removal values were achieved.

69 citations


Journal ArticleDOI
TL;DR: In this paper, the anodic voltammetric behavior of 4-Nitrophenol on a Boron-doped diamond electrode in aqueous solution has been studied using square wave voltammetry.
Abstract: The anodic voltammetric behavior of 4-Nitrophenol on a Boron-doped diamond electrode in aqueous solution has been studied using square wave voltammetry. After optimization of the experimental conditions, that model molecule was analyzed in pure water solutions using a Britton-Robinson buffer with pH 6.0 as the supporting electrolyte. Oxidation occurs at 1.0 V vs. Ag/AgCl in an irreversible two-electron process controlled by adsorption of the species. The detection limit (DL) obtained was 2.8 mg L-1. This result was comparable to that obtained from reduction of the molecule at -0.8 V vs. Ag/AgCl under the same experimental conditions (DL = 4.2 mg L-1). Both DL values are within the limits required by the legislation for drinking water (30 mg L-1). The combination of square wave voltammetry and diamond electrodes has proved to be an interesting and desirable alternative for the analytical determination of organic molecules.

69 citations


Journal ArticleDOI
TL;DR: In this paper, the electrocatalytic oxidation of methanol at a glassy carbon electrode modified by a thin film of poly(o-aminophenol) (PoAP) containing Pt, Pt-Ru and Pt-Sn microparticles has been investigated using cyclic voltammetry as analytical technique and 0.10m perchloric acid as supporting electrolyte.
Abstract: The electrocatalytic oxidation of methanol at a glassy carbon electrode modified by a thin film of poly(o-aminophenol) (PoAP) containing Pt, Pt-Ru and Pt-Sn microparticles has been investigated using cyclic voltammetry as analytical technique and 0.10 M perchloric acid as supporting electrolyte. It has been shown that the presence of PoAP film increases considerably the efficiency of deposited Pt microparticles toward the oxidation of methanol. The catalytic activity of Pt particles is further enhanced when Ru or specially Sn is co-deposited in the polymer film. The effects of various parameters such as the thickness of polymer film, concentration of methanol, medium temperature as well as the long term stability of modified electrodes have also been investigated.

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate that efficient DMFC electrocatalysts can be achieved by Ru deposition on carbon-supported Pt nanoparticles, and that formation of a PtRu alloy is not a required condition for effective methanol electrooxidation.
Abstract: Methanol oxidation electrocatalysts were prepared from Ru electrochemical or spontaneous deposition on commercial-grade carbon-supported Pt nanoparticles (Pt-Vulcan XC72, E-TEK). The resulting Ru coverage was estimated by cyclic voltammetry in supporting electrolyte. The maximum electrocatalytic activity for methanol oxidation at room temperature was observed at lower Ru coverage for spontaneous deposition than for electrodeposition; θRu ∼10% vs ∼20%, respectively. On the other hand, higher current densities for methanol oxidation were obtained in the case of electrodeposited Ru. These two results were related to the presence of non-reducible ruthenium oxides in the spontaneous deposit. The present work provides evidence that (i) efficient DMFC electrocatalysts can be achieved by Ru deposition on Pt nanoparticles, and (ii) formation of a PtRu alloy is not a required condition for effective methanol electrooxidation.

Journal ArticleDOI
TL;DR: In this article, a potentiometric method has been developed and tested using the Nafion membrane for assessing CH 3 OH crossover by an easier and faster method than the conventional CO 2 analysis method.

Journal ArticleDOI
TL;DR: In this paper, two Cu2+ sandwich-type heteropolyanions with the Dawson moiety [X2W15O56]12− (X=P or As) were synthesized.

Journal ArticleDOI
TL;DR: In this article, the in situ conductivity vs p-doping charge of low-defect polypyrroles, N-substituted poly pyrrole, and polythiophenes has been investigated in acetonitrile in the presence of the weakly coordinating perchlorate ion as supporting electrolyte.
Abstract: The in situ conductivity vs p-doping charge of low-defect polypyrroles, N-substituted polypyrroles, and polythiophenes has been investigated in acetonitrile in the presence of the weakly coordinating perchlorate ion as supporting electrolyte. In-situ ESR and EQCM measurements have given supporting information on polymer structure and conduction carriers. The structures of the polymers cover a wide range of conjugative, geometrical, and solvation conditions, but the conductive pattern follows simply the polymer ring type (pyrrole, N-substituted pyrrole, or thiophene). In polythiophenes an initial region of low conductivity, due to strongly spin-dimerized polarons, is followed by an increase of conduction to a plateau of high conductivity. N-substituted polypyrroles display a linear increase of conductivity with charge followed by a plateau of conductivity. Polypyrroles without N-substitution show an increase of conductivity to a maximum followed by a symmetrical decrease to zero at a charge corresponding t...

Journal ArticleDOI
TL;DR: Kinetic parameters, Michaelis-Menten constant, K(m), and the maximum reaction rate, V(max), were investigated and Operational stability and temperature optimization of the enzyme electrodes were also examined.

Journal ArticleDOI
TL;DR: A detailed investigation on the electrochemical reduction of oxygen was carried out using cyclic voltammetry at a glassy carbon electrode in dimethylsulphoxide (DMSO) containing 0.1 M tetrabutylammonium perchlorate (TBAP) as the supporting electrolyte.

Journal ArticleDOI
TL;DR: In this article, invertase and glucose oxidase in conducting polypyrrole and copolymers of poly 2-methylbutyl-2-(3-thienyl) acetate with pyrrole were achieved via electrochemical method.

01 Jan 2003
TL;DR: In this paper, the effect of doping and supporting electrolyte anions' effect on the potentiometric sensitivity and response time of polypyrrole (PPy) electrodes towards changes of solution pH were studied.
Abstract: The pH sensitivity of conducting polymer films is an important issue from the sensor design point of view. The doping and supporting electrolyte anions' effect on the potentiometric sensitivity and response time of polypyrrole (PPy) electrodes towards changes of solution pH were studied. It was found that (i) the response of PPy doped by easily exchangeable com- mon anions (Cl � ,N O 3 � , ClO4 � ) in their solutions (KCl, KNO3, NaClO4) is slow. In contrast, (ii) poly- pyrrole films deposited in the presence of weak acid anions (phthalates, oxalates, salicylates) were charac- terised by instantaneous responses in the above men- tioned solutions. On the basis of electrochemical experiments (open circuit potential vs. time dependen- cies, cyclic voltammetry, EQCM), the observed differ- ences were attributed to different mechanisms of pH sensitivity of tested films. The long response times are related to the incorporation of the solution ions into the film in order to compensate charges created due to protonation. On the other hand, if the ion-exchange is hindered as in the case of (ii), instantaneous open circuit responses are observed due to polarisation of the oxidised polymer layer, analogously to the metal elec- trode. Moreover, for these films the internal pH buffer- ing within the polymer membrane will weaken the pH change effect. The mechanisms were confirmed in the course of studying the pH effect in solutions containing anions easily (KCl, NaClO4, KNO3) or hardly exchangeable with polypyrrole (K2SO4, sodium poly(4-styrenesul- phonate) solutions) acidified with H2SO4.

Journal ArticleDOI
TL;DR: In this article, the effect of doping and supporting electrolyte anions on the potentiometric sensitivity and response time of polypyrrole (PPy) electrodes towards changes of solution pH were studied.
Abstract: The pH sensitivity of conducting polymer films is an important issue from the sensor design point of view. The doping and supporting electrolyte anions’ effect on the potentiometric sensitivity and response time of polypyrrole (PPy) electrodes towards changes of solution pH were studied. It was found that (i) the response of PPy doped by easily exchangeable common anions (Cl−, NO3 −, ClO4 −) in their solutions (KCl, KNO3, NaClO4) is slow. In contrast, (ii) polypyrrole films deposited in the presence of weak acid anions (phthalates, oxalates, salicylates) were characterised by instantaneous responses in the above mentioned solutions. On the basis of electrochemical experiments (open circuit potential vs. time dependencies, cyclic voltammetry, EQCM), the observed differences were attributed to different mechanisms of pH sensitivity of tested films. The long response times are related to the incorporation of the solution ions into the film in order to compensate charges created due to protonation. On the other hand, if the ion-exchange is hindered as in the case of (ii), instantaneous open circuit responses are observed due to polarisation of the oxidised polymer layer, analogously to the metal electrode. Moreover, for these films the internal pH buffering within the polymer membrane will weaken the pH change effect.

Journal ArticleDOI
TL;DR: In this paper, the influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o-anisidine), poly (o-toluidine), and poly(nisidine-co-o-tealuidine) thin films was investigated, where homopolymer and copolymer thin films were synthesized electrochemically under cyclic voltammetry conditions.
Abstract: The influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o-anisidine), poly(o-toluidine), and poly(o-anisidine-co-o-toluidine) thin films was investigated. Homopolymer and copolymer thin films were synthesized electrochemically, under cyclic voltammetry conditions, in aqueous solutions of inorganic acids (H2SO4, HCl, HNO3, H3PO4, and HClO4) and organic acids (benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid) at room temperature. The films were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and conductivity measurements with a four-probe technique. The ultraviolet–visible spectra were obtained ex situ in dimethyl sulfoxide. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic electrolytes used, whereas in organic acid supporting electrolytes, ES formed only with oxalic acid. Moreover, the current density and conductivity of the thin films was greatly affected by the nature and size of the anion present in the electrolyte. For the copolymer, the conductivity lay between the conductivity of the homopolymers, regardless of the supporting electrolyte used. The formation of the copolymer was also confirmed with differential scanning colorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2634–2642, 2003

Journal ArticleDOI
TL;DR: In this paper, the problem of the application of perchloric acid and/or perchlorate supporting electrolyte in electrochemical and corrosion studies is discussed and it is demonstrated that in contrast to the general view in the literature the reduction of per chlorate ions could be an important step in the overall process occurring in the course of spontaneous dissolution of some metals in acid perchlorates medium, especially in the case of the dissolution of iron.

Journal ArticleDOI
Juichi Arai1
TL;DR: In this paper, the use of no-flash-point electrolytes (NFEs) containing non-flammable solvent for an amorphous carbon/Li 1+x Mn 2 O 4 /Li cell has been studied.

Journal ArticleDOI
Tak-Hyun Kim1, Tak-Hyun Kim2, Chulhwan Park2, Eung-Bai Shin1, Sangyong Kirm2 
TL;DR: In this paper, Cl-based chemical coagulation was employed as the pretreatment step for the preremoval of suspended and colloidal solids which impede electrochemical oxidation.

Journal ArticleDOI
TL;DR: In this paper, Nafion® perfluorinated polymer was applied to indium-tin oxide electrodes (ITO) by using Langmuir-Schaefer (LS) technique, after optimization of the subphase composition conditions.
Abstract: Ultrathin films of Nafion® perfluorinated polymer were deposited on indium-tin oxide electrodes (ITO) by using Langmuir-Schaefer (LS) technique, after optimization of the subphase composition conditions. Morphological characteristics of these coatings were obtained by Atomic Force Microscopy (AFM). Nafion® LS films showed a good uniformity and complete coverage of the electrode surface, however a different organization degree of the polymer layer was evidenced with respect to thin films deposited by spin-coating. ITO electrodes modified with Nafion® LS coatings preconcentrate by ion-exchange electroactive cations, such as Ru[(NH3)6]3+, dissolved in diluted solutions. The electroactive species is retained by the Nafion® LS coated ITO also after transfer of the modified electrode into pure supporting electrolyte. This allowed the use of the ruthenium complex as voltammetric probe to test diffusion phenomena within the Nafion® LS films. Apparent diffusion coefficients (Dapp) of Ru[(NH3)6]3+ incorporated in Nafion® LS films were obtained by voltammetric measurements. Dapp values decrease slightly by increasing the amount of ruthenium complex incorporated in the ultrathin film. They are significantly lower than values typical for recasted Nafion® films, in agreement with the highly condensed nature of the Nafion® LS fims.

Journal ArticleDOI
TL;DR: In this paper, a thin palladium pentacyanonitrosylferrate (PdPCNF) film was applied on the surface of an aluminum substrate and the effect of pH, ammonium, alkali metal and alkaline earth metal cations of supporting electrolyte on the electrochemical characteristics of the modified electrode was studied.

Journal ArticleDOI
TL;DR: In this paper, three newly synthesized polyanthraquinone derivatives: 7,13-bis(9,10dioxo-1-anthryl)-1,4,10-trioxa-7, 13-diazacyclopentadecane, (AQNet)3N, were examined by cyclic and normal pulse voltammetry.
Abstract: Three newly synthesized polyanthraquinone derivatives: 7,13-bis(9,10-dioxo-1-anthryl)-1,4,10-trioxa-7,13-diazacyclopentadecane, (AQ)A215C5, 7,16-bis(9,10-dioxo-1-anthryl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, (AQ)A218C6, and tris[(9,10-diokso-1-antryl)-aminoethyl]amine, (AQNet)3N, were examined by cyclic and normal pulse voltammetry All anthraquinone groups in these compounds were electroactive and formed the radicals and dianions similarly to simple anthraquinone The differences between the voltammograms obtained in the absence and presence of supporting electrolyte are discussed, and the diffusion coefficients of the compounds and the rates of the chemical reactions following the first reduction step were evaluated (AQNet)3N appears to be a good model compound for multi electron transfers in aprotic solvents It offers two consecutive nearly reversible 3-electron redox systems: 0/−3 and −3/−6 The interactions of the radicals and dianions of the above compounds with alkali metal cations were examined

Journal ArticleDOI
TL;DR: A liquid chromatography with an electrochemical detector method has been developed for the quantitative measurement for three diamine derivatives in human urine and rabbit blood, urine, and feces.

Journal ArticleDOI
TL;DR: In this article, the electrochemical oxidation of dilute aqueous solutions of pentachlorophenol (PCP) using Ti/SnO2 as an electrocatalytic material has been investigated.
Abstract: The electrochemical oxidation of dilute aqueous solutions of pentachlorophenol (PCP) using Ti/SnO2 as an electrocatalytic material has been investigated The studies were carried out in a two-compartment electrochemical cell at three different current density values (10, 30 and 50 mA cm–2) at 25 °C and using 20 mg L–1 of PCP in 01 M NaOH (pH 10) as supporting electrolyte The PCP concentration and the by-products of the oxidized solution were monitored during the oxidation process using UV and HPLC techniques For the three current densities investigated it was found that the rate of PCP elimination depends only on the specific electrical charge Likewise, the oxidation mechanism was proved to occur through the participation of adsorbed hydroxyl radicals (·OH) formed on the SnO2 surface, whatever the current density used However, as the applied current density was increased, a current efficiency lower than 2% was obtained, which is due to mass transfer limitations In addition, it was observed that the PCP was mineralized to CO2 with conversion percentages as high as 92% and at current density values as low as 10 mA cm–2 The PCP degradation produces two other by-products of oxidation (<10%), namely carboxylic acids, which are non-toxic compounds

Journal ArticleDOI
15 May 2003
TL;DR: The specific adsorption of radiolabeled sulfate ions from perchlorate supporting electrolyte onto TiO2 powder (anatase) has been investigated and Langmuir-like adsorptive behavior similar to that on other oxides was found.
Abstract: The specific adsorption of radiolabeled sulfate ions from perchlorate supporting electrolyte onto TiO2 powder (anatase) has been investigated. The pH and concentration dependence of the adsorption was determined. Langmuir-like adsorption behavior similar to that on other oxides was found. From the pH dependence it follows that the protonation of the surface should precede the specific anion adsorption. The results obtained are compared with those reported for TiO2 bulk electrodes.