Results 1 - 10 of 25403
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[en] A re-usable in-situ-SQUID electrochemical cell for magnetisation studies during electrochemical cycling is presented. The proof of function is demonstrated by recording reversible magnetisation changes in LiFeO nanoparticles upon electrochemical cycling. The data imply the transition from inverse spinel structure (x=0) to a rocksalt phase (x=2). In addition, the setup is utilised to study the effect of lithiation on the Mott-Hubbard transition in VO.
[en] Conditions for electrochemical generation of cerium(IV) at glassy carbon in acetic acid in the presence of alkali-metal acetates and sodium perchlorate, respectively, were investigated. A high current efficiency was achieved in anodic oxidation of cerium(III) in acetate supporting electrolytes. Coulometric titration methods for the determination of reducing substances with the generated oxidant were also developed. The end-points were determined by the biamperometric and bipotentiometric methods. The error of the determinations was less than ± 2%
[en] The purpose of the paper is to delineate the structure of moder electrochemistry and to elucidate the manner in which electrochemical ideas and techniques contribute to the development of power sources and the the advancement of energy science. One example of such an application is the prevention of corrosion in the coolant circuit of a nuclear power station, or its decontamination; another is the use of electrolysis for final upgrading of heavy water. (N.D.H.)
[en] Highlights: • Very high-order spatial discretisations in electrochemical simulations are tested. • Asymmetric 4-to7-point approximations enable to use grids with less than 15 points. • Brute force resolution of the resulting problem is competitive in all cases studied. • Comparison between LU and QR decompositions and sparse matrix methods is performed. • Easy-to-implement, C++ example programs are provided. The use of very high order spatial discretisation in digital simulation of electrochemical experiments is assessed, considering up to asymmetric 8-point approximations for the derivatives. A wide range of conditions are examined, including several mechanisms and electrodes and potential-step and potential-sweep experiments. In all cases it is found that asymmetric multi-point approximations in combination with exponentially expanding grids provides very accurate results and with very reduced number of grid points (<15). Consequently, the direct (‘brute force’) resolution of the finite-difference equation system by standard matrix techniques becomes a competitive and more general alternative to specialised methods like the Thomas algorithm.
[en] The electrochemical determination of methdilazine (MDH), an antihistamine drug was carried out using glassy carbon sensor modified with multi-walled carbon nanotubes (MWCNTs) in pH 9.0 phosphate buffer solution (PBS). Various voltammetric techniques were employed to study the effect of accumulation time, pH, scan rate, excipients, metal ions, concentration on the MDH voltammetric behavior. Based on the relation between scan rate and peak potential value, a probable electro-oxidation mechanism was proposed. The lower detection limit value was obtained in the quantitative determination of MDH ranging from 0.1 × 10−7 M to 0.3 × 10−6 M. The proposed sensor showed an excellent response to all the parameters and was able to apply to analyze MDH in urine and pharmaceutical samples. (paper)
[en] Highlights: • The electrochemical synthesis of poly(o-methoxyaniline) (POMA) thin films was performed. • The concentration of monomer, and anodic charge influence the POMA film formation. • A relationship between the mass of the POMA, the anodic charge, and concentration of the OMA was established by EQCM studies. • The morphology of the films shows a compact first layer with spherical grains of different sizes distributed in this layer.