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Composite Electrode (composite + electrode)

Distribution by Scientific Domains

Chemistry	60%
Polymers and Materials Science	32%

Selected Abstracts

Simultaneous Determination of Cadmium, Lead, Copper and Mercury Ions Using Organofunctionalized SBA-15 Nanostructured Silica Modified Graphite,Polyurethane Composite Electrode

ELECTROANALYSIS, Issue 1 2010
Ivana Cesarino
Abstract A new sensor has been developed for the simultaneous detection of cadmium, lead, copper and mercury, using differential pulse and square wave anodic stripping voltammetry (DPASV and SWASV) at a graphite,polyurethane composite electrode with SBA-15 silica organofunctionalized with 2-benzothiazolethiol as bulk modifier. The heavy metal ions were preconcentrated on the surface of the modified electrode at ,1.1,V vs. SCE where they complex with 2-benzothiazolethiol and are reduced to the metals, and are then reoxidized. Optimum SWASV conditions lead to nanomolar detection limits and simultaneous determination of Cd2+, Pb2+, Cu2+ and Hg2+ in natural waters was achieved. [source]

Adsorptive Stripping Voltammetric Detection of Tea Polyphenols at Multiwalled Carbon Nanotubes-Chitosan Composite Electrode

ELECTROANALYSIS, Issue 6 2009
Deyin Guo
Abstract This study reports the catalytic oxidation and detection of tea polyphenols (TPs) at glassy-carbon electrode modified with multiwalled carbon nanotubes-chitosan (MWCNTs-CS) film. The adsorption of TPs at the surface of the MWCNTs through ,,, conjugation prevents the aggregation of nanotubes and induces a stable MWCNTs suspension in water over 30 days. Based on the adsorptive accumulation of polyphenols at MWCNTs, TPs is sensitively and selectively detected by adsorptive stripping voltammetry. The accumulation conditions and pH effect on the adsorptive stripping detection were examined. The linear range was found to be 100 to 1000,mg L,1 with a detection limit of 10,mg L,1 (S/N=3) for 2.5,min accumulation. Additionally, the MWCNTs-CS electrode is easily renewed by applying positive potential to remove the adsorbed TPs. This method was successfully applied to determine TPs in commercially available teas with satisfied result compared with that of conventional spectrometric analysis. [source]

Glucose Biosensor Mediated by 1,2-Diferrocenylethane in a Sono-Gel Composite Electrode

ELECTROANALYSIS, Issue 2-3 2007
Barbara Ballarin
Abstract An amperometric glucose biosensor was constructed based on a renewable carbon composite sono-gel matrix incorporating 1,2-diferrocenylethane as electron transfer mediator between the electrode and the active site of glucose oxidase. The enzyme was immobilized on the electrode surface by cross-linking with glutaraldehyde and bovine serum albumin. The process parameters for the fabrication of the biosensor and the influence of various experimental conditions (i.e., pH, temperature, operating potential) were investigated. Cyclic voltammetry and amperometric measurements were used to study the response of the glucose sensor, which displayed fast response time and good reproducibility. The analytical performances and the apparent Michaelis-Menten constant of the biosensor were evaluated. [source]

Determination of Rutin in Green Tea Infusions Using Square-Wave Voltammetry with a Rigid Carbon-Polyurethane Composite Electrode

ELECTROANALYSIS, Issue 10 2006
Andréa
Abstract This paper presents a comparative study on the electrochemical behavior of the flavonoid rutin on a rigid carbon-polyurethane composite electrode and on a glassy carbon electrode. The electrochemical oxidation reaction of rutin was found to be quasireversible and affected by adsorption on the electrode surface. A square-wave voltammetric method was developed for determination of rutin in green tea infusion samples using the RCPE electrode and data treatment by a deconvolution procedure. The detection limit achieved in buffered solutions was 7.1×10,9,mol L,1 using the RCPE and 1.7×10,8,mol L,1 using the GC electrode the average reproducibility for five determinations being 3.5%. [source]

Voltammetric Determination of Phenylglyoxylic Acid in Urine Using Graphite Composite Electrode

ELECTROANALYSIS, Issue 2 2006
Navrátil
Abstract A composite electrode prepared from graphite powder and epoxy resin was applied as a working electrode for the determination of phenylglyoxylic acid (one of the metabolites of styrene) in human urine. Cathodic differential pulse stripping voltammetry was used and optimum conditions have been found giving the limit of determination about 5,mg L,1. All results were compared with those obtained using hanging mercury drop electrode. For the confirmation of suggested mechanism of the electrochemical reaction the elimination voltammetry with linear scan was used. [source]

A Transparent, Flexible, Low-Temperature, and Solution-Processible Graphene Composite Electrode

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2010
Haixin Chang
Abstract The synthesis and preparation of a new type of graphene composite material suitable for spin-coating into conductive, transparent, and flexible thin film electrodes in ambient conditions is reported here for the first time. Solution-processible graphene with diameter up to 50 ,m is synthesized by surfactant-assisted exfoliation of graphite oxide and in situ chemical reduction in a large quantity. Spin-coating the mixing solution of surfactant-functionalized graphene and PEDOT:PSS yields the graphene composite electrode (GCE) without the need for high temperature annealing, chemical vapor deposition, or any additional transfer-printing process. The conductivity and transparency of GCE are at the same level as those of an indium tin oxide (ITO) electrode. Importantly, it exhibits high stability (both mechanical and electrical) in bending tests of at least 1000 cycles. The performance of organic light-emitting diodes based on a GCE anode is comparable, if not superior, to that of OLEDs made with an ITO anode. [source]

A Multiscale Description of the Electronic Transport within the Hierarchical Architecture of a Composite Electrode for Lithium Batteries

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009
Jean-Claude Badot
Abstract The broadband dielectric spectroscopy technique is applied, for the first time, to a composite material used as an electrode for lithium battery. The electrical properties (permittivity and conductivity) are measured from low (a few Hz) to microwave (a few GHz) frequencies. The results demonstrate that the broadband dielectric spectroscopy technique is very sensitive to the different scales of the electrode architecture involved in electronic transport, from interatomic distances to macroscopic sizes, as well as to the morphology at these scales, coarse or fine distribution of the constituents. This work opens up new prospects for a more fundamental understanding and more rational optimization of the electronic transport in composite electrodes for lithium batteries and other electrochemical energy storage technologies (including other batteries, supercapacitors, low- and medium-temperature fuel cells), electrochemical sensors and conductor,insulator composite materials. [source]

Glucosinolate Amperometric Bienzyme Biosensor Based on Carbon Nanotubes-Gold Nanoparticles Composite Electrodes

ELECTROANALYSIS, Issue 13 2009
V. Serafín
Abstract A novel electrochemical biosensor design for glucosinolate determination involving bulk-incorporation of the enzymes glucose oxidase and myrosinase into a colloidal gold - multiwalled carbon nanotubes composite electrode using Teflon as binder is reported. Myrosinase catalyzes the hydrolysis of glucosinolate forming glucose, which is enzymatically oxidized. The generated hydrogen peroxide was electrochemically detected without mediator at the nanostructured composite electrode at E=+0.5,V vs. Ag/AgCl. Under the optimized conditions, the bienzyme MYR/GOx-Aucoll -MWCNT-Teflon exhibited improved analytical characteristics for the glucosinolate sinigrin with respect to a biosensor constructed without gold nanoparticles, i.e. a MYR/GOx-MWCNT-Teflon electrode, as well as with respect to other glucosinolate biosensor designs reported in the literature. The biosensor exhibits good repeatability of the amperometric measurements and good interassay reproducibility. Furthermore, the biosensor exhibited a high selectivity with respect to various potential interferents. The usefulness of the biosensor was evaluated by the determination of glucosinolate in Brussel sprout seeds. [source]

Differential Pulse Voltammetric Determination of Selected Nitro-Compounds on Silver, Solid Silver Composite, and Solid Graphite Composite Electrodes

ELECTROANALYSIS, Issue 3-5 2009
Navrátil
Abstract Three different types of solid electrodes, namely silver electrode, silver composite electrode containing 20% (m/m) of silver powder, 20% (m/m) of graphite powder and 60% (m/m) of methacrylate resin and graphite composite electrode containing 30% (m/m) of graphite powder and 70% (m/m) of epoxy resin were tested for differential pulse voltammetric determination of selected genotoxic nitro-compounds using 2-nitronaphthalene, 6-nitroquinoline, and 5-nitrobenzimidazole as model compounds. It was found that all three electrodes can be used for the determination of micromolar concentrations of tested model substances, the limit of detection and other figures of merits being dependent both on the electrode used and the substance to be determined. [source]

Amperometric Detection of 4-Chlorophenol on Two Types of Expanded Graphite Based Composite Electrodes

ELECTROANALYSIS, Issue 22 2008
Aniela Pop
Abstract The assessment of an expanded graphite-Ag-zeolite-epoxy composite (EG-Z-Ag-Epoxy) electrode for the determination of 4-chlorophenol (4-CP) is described and compared to the corresponding expanded graphite-epoxy composite (EG-Epoxy) electrode. Cyclic voltammetry was used to characterize the electrochemical behavior and determination of 4-CP at both electrodes in 0.1,M Na2SO4 and 0.1,M NaOH supporting electrolytes. A substantial enhancement of sensitivity for the determination of 4-CP at the EG-Z-Ag-Epoxy electrode was reached by applying a chemical preconcentration step prior to voltammetric quantification. Also, under these last conditions the lowest limit of detection of 1,,M illustrates the analytical versatility of this electrode in a concentration range where aquatic 4-chlorophenol pollution is known to occur. [source]

Copper Oxide , Graphite Composite Electrodes: Application to Nitrite Sensing

ELECTROANALYSIS, Issue 1 2007
Biljana, ljuki
Abstract A simple method for the modification of carbon powder with copper oxides is presented. Carbon powder is impregnated with copper(II) nitrate by stirring carbon powder in copper(II) nitrate solution for 1 hour and subsequently thermally treated at 823,K. The modified carbon powder was characterized using electrochemical and spectroscopic techniques. The existence of both copper(I) and copper(II) oxides have been established. The copper oxide modified carbon powder was used for preparation of composite electrodes, and the electrochemical and electrocatalytic behavior of the resulting composite electrodes was studied. The copper oxide modified carbon powder , epoxy composite electrodes showed a high electrocatalytic activity for the nitrite detection in aqueous media, with the detection limit comparable or lower than detection limits obtained with other electrochemical sensors. [source]

Ultrathin Direct Atomic Layer Deposition on Composite Electrodes for Highly Durable and Safe Li-Ion Batteries

ADVANCED MATERIALS, Issue 19 2010
Yoon Seok Jung
Direct atomic layer deposition (ALD) on composite electrodes leads to ultrathin conformal protective coatings without disrupting inter-particle electronic pathways. Al2O3 -coated natural graphite (NG) electrodes obtained by direct ALD on the as-formed electrode show exceptionally durable capacity retention even at an elevated temperature of 50,°C. In sharp contrast, ALD on powder results in poorer cycle retention than bare NG. [source]

Simultaneous Determination of Cadmium, Lead, Copper and Mercury Ions Using Organofunctionalized SBA-15 Nanostructured Silica Modified Graphite,Polyurethane Composite Electrode

Glucosinolate Amperometric Bienzyme Biosensor Based on Carbon Nanotubes-Gold Nanoparticles Composite Electrodes

Determination of Rutin in Green Tea Infusions Using Square-Wave Voltammetry with a Rigid Carbon-Polyurethane Composite Electrode

Voltammetric Determination of Phenylglyoxylic Acid in Urine Using Graphite Composite Electrode

Carbon nanotube/poly(methyl methacrylate) composite electrode for capillary electrophoretic measurement of honokiol and magnolol in Cortex Magnoliae Officinalis

ELECTROPHORESIS, Issue 16 2006
Xiao Yao
Abstract This paper describes the development and the application of a novel carbon nanotube/poly(methyl methacrylate) (CNT/PMMA) composite electrode as a sensitive amperometric detector of CE. The composite electrode was fabricated on the basis of the in,situ polymerization of a mixture of CNT and prepolymerized methylmethacrylate in the microchannel of a piece of fused-silica capillary under heat. The performance of this unique system has been demonstrated by separating and detecting honokiol and magnolol in traditional Chinese medicine, Cortex Magnoliae Officinalis. Factors influencing their separation and detection processes were examined and optimized. Honokiol and magnolol were well separated within 7,min in a 40 cm long capillary at a separation voltage of 15,kV using a 50 mM borate buffer (pH,9.2). The new CNT-based CE detector offered significantly lower operating potentials, yielded substantially enhanced S/N characteristics, and exhibited resistance to surface fouling and hence enhanced stability. It demonstrated long-term stability and reproducibility with RSDs of less than 5% for the peak current (n = 9) and should also find a wide range of applications in microchip CE, flowing injection analysis, and other microfluidic analysis systems. [source]

A Transparent, Flexible, Low-Temperature, and Solution-Processible Graphene Composite Electrode

Copper Oxide , Graphite Composite Electrodes: Application to Nitrite Sensing

Carbon Nanotubes: High Electromechanical Response of Ionic Polymer Actuators with Controlled-Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Mater.
Abstract Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here, experiments demonstrate that the VA-CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 V). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultrahigh volume fraction VA-CNTs to further enhanced performance. [source]

High Electromechanical Response of Ionic Polymer Actuators with Controlled-Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Sheng Liu
Abstract Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here, experiments demonstrate that the VA-CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 V). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultrahigh volume fraction VA-CNTs to further enhanced performance. [source]

A Multiscale Description of the Electronic Transport within the Hierarchical Architecture of a Composite Electrode for Lithium Batteries

Activated carbon-polyethylenedioxythiophene composite electrodes for symmetrical supercapacitors

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008
M. Selvakumar
Abstract A symmetrical (p/p) supercapacitor has been fabricated by making use of activated carbon (AC)-polyethylenedioxythiophene (PEDOT)-composite electrodes for the first time. The composite electrodes have been prepared via electrochemical deposition of ,-napthalenesulphonate doped PEDOT onto AC electrodes. The characteristics of the electrodes and the fabricated supercapacitor have been investigated using cyclic voltammetry (CV) and AC impedance spectroscopy. The electrodes show a maximum specific capacitance of 158 Fg,1 at a scan rate of 10 mV s,1. This indicates that the in situ electro-polymerization of ethylenedioxythiophene (EDOT) onto AC could improve the performance of carbon electrodes for use in supercapacitors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source]

In situ Chemical Deposition of Polyaniline on Activated Carbon for Electrochemical Capacitors

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2006
Zhang-Hua Zhou
Abstract Polyaniline (PA) film was chemically deposited onto the surface of activated carbon (AC) uniformly. Chemical deposition was carried out in 0.1 mol/L aniline plus 0.5 mol/L H2SO4 solution adopting V2O5·nH2O coated on the surface of activated carbon as oxidant. The surface morphologies and structures of the composite materials were characterized by scanning electron microscopy and FT-IR spectra. The electrochemical properties of the composite material electrodes were studied by cyclic voltammetry and constant current charge/discharge tests in 1 mol/L H2SO4 solutions. The specific capacitance of composite materials was exhibited as high as 237.5 F/g at a current density of 1.0 A/g compared with a value of 120 F/g for pure carbon electrode. Good power characteristic and good stability of composite electrodes were also demonstrated. [source]