Search results for "electrode"

Nickel(II) Complex of a Hexadentate Ligand with Two o-Iminosemiquinonato(1-) π-Radical Units and Its Monocation and Dication.

2016

Aerobic reaction of a hexadentate redox-active o-aminophenol-based ligand, H4L(3) = N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2'-diamino(diphenyldithio)-ethane, in CH3OH with Ni(II)(O2CCH3)2·4H2O and Et3N afforded isolation of a reddish-brown crystalline solid [Ni(L(3))] 1. Cyclic voltammetry (CV) experiment exhibits two oxidative responses at E1/2 = 0.09 and 0.53 V vs SCE (saturated calomel electrode). Chemical oxidation of 1 in air by [Fe(III)(η(5)-C5H5)2][PF6] and AgBF4 in CH2Cl2 led to the isolation of one-electron oxidized species [1](1+) as purple [1][PF6]·CH2Cl2 and two-electron oxidized species [1](2+) as dark purple [1][BF4]2·CH2Cl2, respectively. X-ray crystallographic analysi…

Electrocatalytic properties of ferrooctacarboxyphthalocyanine(II). Electrocatalytic oxygen reduction on the mercury electrode in aqueous solutions

1996

Electrocatalytic reduction of oxygen in aqueous solutions in the presence of ferrooctacarboxyphthalocyanine was investigated. The decay of catalytic properties is attributed to the phthalocyanine aggregation. The mechanism for the four-electron electrocatalytic O2-reduction in neutral and basic media involving FePc(COOH)8 is proposed. It has been found that monomers of phthalocyanine, which are able to form μ-peroxo structures, are the catalytically active forms. The adsorption of various phthalocyanine forms on the mercury electrode plays a very important role in the overall catalytic reaction.

Ni-Based Alloy Nanostructured Electrodes for Alkaline Electrolyzers

In water alkaline electrolyzer field, the development of Nickel-based nanostructured electrode is one of the possible ways to improve the water electrolysis efficiency

An improved cathode for alkaline fuel cells

2010

Abstract The use of nickel foam as an electrode substrate in alkaline fuel cells (AFCs) has been investigated for bipolar cells incorporating an electrically conducting gas diffusion layer (GDL). Improved performance, compared to a previous design, was obtained by adding an extra active layer (AL) composed of manganese (IV) oxide (MnO2) deposited onto carbon black. This new cathode design performed significantly better (130 mA cm−2 at 0.8 V and 25 °C) than the previous design (35 mA cm−2 under the same condition), especially at higher potential. It has been shown that the GDL is a key component of the gas diffusion electrode for both performance and durability, especially with liquid electr…

Influence of mass transport on the competition between corrosion of aluminium alloy surface and the release of primer containing inhibitors : validat…

2014

The conventional aircraft paint scheme for corrosion protection of aluminum structures is partly based on application of a primer containing inhibitors. In such coatings, release of the inhibiting species enables fast healing of a bare metal surface after a mechanical damage of the protective layers. Nevertheless, considering possible depletion of inhibitors by uncontrolled leaching, it appears important to estimate the corrosion risk integrating “corrosion” sensors in the structure. The objective of this work was to understand the operating mode of a sensor simulating a damaged paint coating whose concept is based on the competition between the triggering of localized corrosion and the pas…

Determination of Bisulfites in Wines with an Electronic Tongue Based on Pulse Voltammetry

2009

Electronic tongues were developed some ten years ago. These systems consist of an array of nonspecific sensors and a signal processing unit. The sensor signals are processed by pattern recognition methods which makes possible the extraction of specific properties from the sample. Depending on the calibration, attributes such as quality or taste can be determined. These systems also detect changes in the sample that they are not calibrated for which makes possible the detection of anomalous occurrences. Such sensor systems are suitable for process control and surveillance. Important factors are the sensitivity and stability, specifically the sensor's ability to respond to small changes and t…

Cyclam-functionalized silica-modified electrodes for selective determination of Cu(II)

2009

Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In p…

Science based calibration for the extraction of 'analyte-specific' HPLC-DAD chromatograms in environmental analysis

2010

Multivariate science based calibration (SBC) has been applied to the resolution of overlapped peaks in liquid chromatography with diode array detection (LC-DAD). Complex river water samples spiked with 11 pharmaceutical substances resulted in poorly resolved chromatograms containing additional peaks from interfering matrix compounds and a change in the background absorbance due to the mobile phase gradient. Applying the present multivariate approach it was possible to resolve all 11 analytes from overlapping peaks, obtaining linear calibration lines (R2 > 0.96). Recovery percentages on spiked samples ranged between 74.6 and 113.5%, which are quite satisfactory taking into account the low co…

Electrochemical pH Control at Gold Nanowires

2018

In this work, interdigitated arrays of nanowire electrodes are used with one array acting as the working electrode while the other is used to generate the required protons. Finite element simulations of the pH control electrodes were performed to provide insight on the generation and subsequent diffusion of protons. This informed the inter-tine spacing of the electrodes used.. This electrochemical pH control method was then used to enable the detection of analytes of interest.

Graphene and ionic liquids new gel paste electrodes for caffeic acid quantification

2015

Abstract Graphene/ionic liquids nanocomposite gels were synthesized by an electrochemical etching approach and fully characterized under a morphological and structural point of view. For this purpose, several analytical techniques were applied, as HR-TEM/EDX (High Resolution-Transmission Electron Microscopy/Energy Dispersive X-Ray Analysis); FE-SEM/EDX (Field Emission-Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis); XPS (X-Ray Photoelectron Spectroscopy); FT-IR (Fourier Transform-Infrared Spectroscopy) and electrochemical techniques. After the characterization study, nanocomposite-gel paste electrodes were assembled, exhibiting a selective and specific detection toward the ca…