Showing papers on "Cyclic voltammetry published in 2008"
TL;DR: In this paper, by means of the metal reducing bacterium Geobacter sulfurreducens, a strategy to use cyclic voltammetry for the study of anodic bioelectrocatalytic electron transfer in microbial fuel cells was discussed.
Abstract: In this communication we discuss, by means of the metal reducing bacterium Geobacter sulfurreducens, a strategy to use cyclic voltammetry for the study of anodic bioelectrocatalytic electron transfer in microbial fuel cells.
472 citations
TL;DR: In this paper, the interfaces formed at glassy carbon electrodes in three low-temperature ionic liquids (1-methyl-3-ethylimidazolium chloride, emimCl, bmimCl; and 1-methyl 3-hexy-limidaxolium-chloride (HmCl), hmCl) were investigated by cyclic voltammetry and impedance spectroscopy.
Abstract: The interfaces formed at glassy carbon electrodes in three low-temperature ionic liquids (1-methyl-3-ethylimidazolium chloride, emimCl; 1-methyl-3-butylimidazolium chloride, bmimCl; and 1-methyl-3-hexylimidazolium chloride, hmimCl) were investigated by cyclic voltammetry and impedance spectroscopy. The potential dependence of the differential double layer capacitance was measured at several temperatures between 80 and 140 °C, and the temperature response was found to be broadly similar to that obtained with high-temperature molten salts. The differential capacitance/potential curves have a minimum and two side branches. The minimum corresponds to the point of zero charge. The differential capacitance increases in the order hmimCl < bmimCl < emimCl because the double layer is thinner when imidazolium (Rmim) cations with shorter alkyl chain lengths are used. The impedance spectra and capacitance curves indicate that cations are adsorbed at the open-circuit potential and that their surface excess concentrati...
456 citations
TL;DR: An inexpensive microporous polyaniline (PANI) is used as a substitute for platinum to construct the counter electrode in dye-sensitized solar cells (DSSCs).
445 citations
TL;DR: These techniques provide the basis for cataloging quantifiable, defined electron transfer phenotypes as a function of potential, electrode material, growth phase, and culture conditions and provide a framework for comparisons with other species or communities.
Abstract: While electrochemical characterization of enzymes immobilized on electrodes has become common, there is still a need for reliable quantitative methods for study of electron transfer between living cells and conductive surfaces. This work describes growth of thin (<20 microm) Geobacter sulfurreducens biofilms on polished glassy carbon electrodes, using stirred three-electrode anaerobic bioreactors controlled by potentiostats and nondestructive voltammetry techniques for characterization of viable biofilms. Routine in vivo analysis of electron transfer between bacterial cells and electrodes was performed, providing insight into the main redox-active species participating in electron transfer to electrodes. At low scan rates, cyclic voltammetry revealed catalytic electron transfer between cells and the electrode, similar to what has been observed for pure enzymes attached to electrodes under continuous turnover conditions. Differential pulse voltammetry and electrochemical impedance spectroscopy also revealed features that were consistent with electron transfer being mediated by an adsorbed catalyst. Multiple redox-active species were detected, revealing complexity at the outer surfaces of this bacterium. These techniques provide the basis for cataloging quantifiable, defined electron transfer phenotypes as a function of potential, electrode material, growth phase, and culture conditions and provide a framework for comparisons with other species or communities.
444 citations
TL;DR: In this article, an asymmetric supercapacitor is constructed using hierarchical porous electrode materials of nickel oxide and carbon with the aim to facilitate ion transport, and the capacitance, energy density and power density of the asymmetric SuperCapACitor can be improved by elevating the supercapACitor voltage, and cycling stability decays at high voltage, but the columbic efficiency stays close to 100%.
420 citations
TL;DR: In this article, a two-electrode cell with a specific capacitance as high as 368 F g−1 was observed, with rectangular cyclic voltammetry curves and stable performance over 10,000 cycles at a cell potential of 1.2 V and current load of 5 A G−1.
420 citations
TL;DR: In this article, a polypyrrole (PPy) nanoparticle was synthesized and coated on a conducting FTO glass to construct PPy counter electrode used in dye-sensitized solar cell (DSSC).
418 citations
TL;DR: In this paper, the current response is interpreted in terms of semi-infinite planar diffusion towards the macro-electrode surface and the oxidation of the electroactive species trapped in pockets in between the carbon nanotubes.
Abstract: Cyclic voltammetry is recorded of the oxidation of ferrocyanide on a glassy carbon electrode modified with multiple layers of single-walled carbon nanotubes. The current response is interpreted in terms of semi-infinite planar diffusion towards the macro-electrode surface and in terms of oxidation of the electroactive species trapped in pockets in between the nanotubes. A thin layer model is used to illustrate the effects of diffusion within a porous layer. It is found that a semi-infinite planar diffusion model alone is not appropriate for interpreting the kinetics of the electron transfer at this electrode surface. In particular, caution should be exercised in respect of comparing voltammetric peak-to-peak potential separations between naked electrodes and nanotube-modified electrodes for the inference of electrocatalysis via electron transfer via the nanotubes.
397 citations
TL;DR: The paper describes the electronic charging and conducting properties of vertically oriented TiO 2 nanotube arrays formed by anodization of Ti foil samples and suggests a route for controlling the electronic properties of the ordered metal-oxide nanostructures for their use in applications including supercapacitors, dye-sensitized solar cells, and gas sensing.
Abstract: The paper describes the electronic charging and conducting properties of vertically oriented TiO2 nanotube arrays formed by anodization of Ti foil samples. The resulting films, composed of vertically oriented nanotubes approximately 10 μm long, wall thickness 22 nm, and pore diameter 56 nm, are analyzed using impedance spectroscopy and cyclic voltammetry. Depending on the electrochemical conditions two rather different electronic behaviors are observed. Nanotube array samples in basic medium show behavior analogous to that of nanoparticulate TiO2 films used in dye-sensitized solar cells: a chemical capacitance and electronic conductivity that increase exponentially with bias potential indicating a displacement of the Fermi level. Nanotube array samples in acidic medium, or samples in a basic medium submitted to a strong negative bias, exhibit a large increase in capacitance and conductivity indicating Fermi level pinning. The contrasting behaviors are ascribed to proton intercalation of the TiO2. Our resu...
375 citations
TL;DR: In this paper, the electrochromic properties of NiO thin films were investigated in an aqueous alkaline electrolyte by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements.
358 citations
TL;DR: It was found that the development of an ordered mesoporous structure and the control of the number of micropores are two important strategies for optimising electrode material properties for electrosorptive deionisation.
TL;DR: In this paper, a biomolecule-assisted hydrothermal process is developed to synthesize cobalt sulfide (CoS), in which l -cysteine is used as the sulfide source and directing molecule.
TL;DR: In this paper, anode electrocatalysts of Ir, Ru and their oxides were prepared and incorporated into the catalyst coated membranes (CCM) of the PEMWE.
TL;DR: A sensitive electrochemical DNA sensor based on nanoporous gold (NPG) electrode and multifunctional encoded Au nanoparticle (AuNP) was developed and exhibited excellent selectivity even for single-mismatched DNA detection.
Abstract: A sensitive electrochemical DNA sensor based on nanoporous gold (NPG) electrode and multifunctional encoded Au nanoparticle (AuNP) was developed. The NPG electrode was prepared with a simple dealloying strategy, by which silver was dissoluted from silver/gold alloys in nitric acid, making the active surface area of NPG electrode 9.2 times higher than that of a bare flat one characterized by cyclic voltammetry. A DNA biosensor was fabricated by immobilizing capture probe DNA on the NPG electrode and hybridization with target DNA, which further hybridized with the reporter DNA loaded on the AuNPs. The AuNP contained two kinds of bio bar code DNA, one was complementary to the target DNA, while the other was not, reducing the cross reaction between the targets and reporter DNA on the same AuNP. Electrochemical signals of [Ru(NH3)6]3+ bound to the reporter DNA via electrostatic interactions were measured by chronocoulometry. Taking advantage of dual-amplification effects of the NPG electrode and multifunctiona...
TL;DR: In this paper, Palladium nanoparticle-loaded carbon nanofibers (Pd/CNFs) were synthesized by the combination of electrospinning and thermal treatment processes.
Abstract: Palladium nanoparticle-loaded carbon nanofibers (Pd/CNFs) were synthesized by the combination of electrospinning and thermal treatment processes. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show that spherical Pd nanoparticles (NPs) are well-dispersed on the surfaces of CNFs or embedded in CNFs. X-ray diffraction (XRD) pattern indicates that cubic phase of Pd was formed during the reduction and carbonization processes, and the presence of Pd NPs promoted the graphitization of CNFs. This nanocomposite material exhibited high electric conductivity and accelerated the electron transfer, as verified by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The Pd/CNF-modified carbon paste electrode (Pd/CNF-CPE) demonstrated direct and mediatorless responses to H2O2 and NADH at low potentials. The analytical performances of the Pd/CNF-CPEs towards reduction of H2O2 and oxidation of NADH were evaluated. The high sensitivity, wider linear range, good reproducibility, and the minimal surface fouling make this Pd/CNF-CPE a promising candidate for amperometric H2O2 or NADH sensor.
TL;DR: In this paper, surface modifications have been made to the activated carbon material, including alkaline treatment and loading of titanium dioxide nanoparticles, and the modified electrode material demonstrated enhanced electrosorption capacity and reduced physical sorption at the pores, so desorption is more efficiently.
TL;DR: In this paper, the authors discuss the application of cyclic voltammetry and impedance spectroscopy to determine the chemical capacitance of mesoporous metal-oxide semiconductors.
TL;DR: In this article, carbon-supported Pt and Pd nanoparticles (CSNs) were synthesized and electrochemically characterized in view of potential application in proton exchange membrane (PEM) water electrolysers.
TL;DR: In this article, a network of CoxNi1−x LDH nanosheets was obtained by using X-ray diffraction analysis, energy dispersive Xray spectroscopy and scanning electron microscopy.
TL;DR: In this paper, a microbial fuel cell (MFC) was constructed using polypyrrole (PPy) coated carbon nanotubes (CNTs) composite as an anode material and Escherichia coli as the biocatalyst.
TL;DR: In this paper, small carbon-supported Pd nanoparticles with controllable size (2.7−9.0 nm) were prepared by a solution chemistry method, characterized by transmission electron microscopy, X-ray diffraction, and Xray photoelectron spectroscopies, and evaluated as anode catalysts for the electrooxidation of formic acid.
Abstract: Small carbon-supported Pd nanoparticles with controllable size (2.7−9.0 nm) were prepared by a solution chemistry method, characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopies, and evaluated as anode catalysts for the electrooxidation of formic acid at room temperature. Measurements of catalytic activity by electrochemical methods (cyclic voltammetry and chronoamperometry) revealed a strong potential-dependent particle size effect. Classical volcano plots of catalytic activity vs particle size were obtained from which the optimal Pd particle size for the respective potential region was determined.
TL;DR: The hydrogen evolution reaction on the electrodeposited Ni-Mo alloy coatings, as well as their electrochemical properties in the NaOH solutions, have been investigated by the polarization measurements, cyclic voltammetry and EIS technique.
TL;DR: In this article, the authors explored a room temperature, simple and low cost chemical route for the cobalt oxide film onto copper substrate from cobalt chloride (CoCl 2 ·6H 2 O) precursor and characterization for its structural and electrochemical properties for supercapacitor application.
TL;DR: In this paper, a core−shell Li3V2(PO4)3@C nanostructured composites were prepared via a sol−gel route followed by hydrothermal treatment.
Abstract: Core−shell Li3V2(PO4)3@C nanostructured composites were prepared via a sol−gel route followed by hydrothermal treatment. XRD patterns showed that Li3V2(PO4)3 has a monoclinic structure with space group P21/n. TEM images exhibited that Li3V2(PO4)3 particles are encapsulated with a carbon shell ∼10 nm in thickness. Compared with pure Li3V2(PO4)3, core−shell Li3V2(PO4)3@C composites presented enhanced electrochemical Li ion intercalation performances. Cyclic voltammetry and electrochemical impedance spectroscopy disclosed that carbon shells improved Li ion diffusion and electrical conductance significantly and also retarded formation of solid electrolyte interphase film of Li3V2(PO4)3 cathode materials.
TL;DR: In this article, a cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution.
TL;DR: The antioxidant activity of five Agaricus sp. mushrooms was screened through chemical, biochemical and electrochemical techniques as discussed by the authors, and it was shown that mushroom extracts revealed similar electrochemical responses, suggesting similar electroactive chemical composition, and oxidation potentials more positive than those of the standards (ascorbic and gallic acids).
TL;DR: Boron-doped carbon nanotubes are the good candidate material for the direct electrochemistry of the redox-active enzyme and the construction of the related enzyme biosensors.
TL;DR: In this article, a corn grains-based activated carbons (CG-ACs) were prepared and their use as electrodes in the electrical double layer capacitor (EDLC) performed successfully.
TL;DR: The ChOx/NanoZnO-CHIT/ITO bioelectrode exhibits linearity from 5 to 300 mg dl(-1) of cholesterol with detection limit, sensitivity and value as well as the value of Michaelis-Menten constant (K(m)) can be used to estimate cholesterol in serum samples.
TL;DR: In this article, a facile method has been developed to synthesize nanoporous manganese and nickel oxides with polyhedron particle morphologies, high surface areas and narrow pore distributions by controlled thermal decomposition of the oxalate precursors.
Abstract: A facile method has been developed to synthesize nanoporous manganese and nickel oxides with polyhedron particle morphologies, high surface areas and narrow pore distributions by controlled thermal decomposition of the oxalate precursors. This method can be extended to using other kinds of salt precursors to prepare a series of nanoporous metal oxides. The heating rate, calcination temperature and controlled particle size of the oxalate precursors are important factors to get well-defined pore structures. XRD, TG-DTA, TEM, SEM, XPS, wet chemical titration and N2 sorption isotherm techniques are employed for morphology and structure characterizations. High surface area microporous manganese oxide (283 m2 g−1) and mesoporous nickel oxide (179 m2 g−1) with narrow pore distribution at around 1.0 nm and 6.0 nm, respectively, are obtained. Especially, we can tune the pore size of manganese oxides from microscope to mesoscope by controlling the thermal procedure. Electrochemical properties of manganese and nickel oxides are studied by cyclic voltammetry measurements in a mild aqueous electrolyte, which shows a high specific capacitance of 309 F g−1 of microporous manganese oxide and a moderately high specific capacitance of 165 F g−1 of mesoporous NiO due to their nanoporous structure, presenting the promising candidates for super capacitors (SC).