The electrochemical reduction of hydrogen peroxide on polycrystalline copper in borax buffer
ABSTRACT The electrochemical reduction of hydrogen peroxide on copper electrodes in a borax buffer has been studied. The effects of surface oxidation and chloride ions in the electrolyte have been investigated. Hydrogen peroxide can be electrochemically reduced on Cu(I) oxidized surfaces. In the absence of chloride, the reduction is catalysed by a redox cycle involving the Cu(I)/Cu(II) couple. In chloride-containing solutions, the surface oxides are dissolved and the reduction becomes more irreversible. There appears to be a change in the reduction mechanism at potentials more negative than −0.45 V.
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ABSTRACT: Detection of 2,4-dinitrotoluene (DNT), which is a common impurity in 2,4,6-trinitrotoluene (TNT)-based explosives is a point of focus in the fight against act of terrorism. In this study, the donor based electrode for the detection of DNT was synthesized by modifying the surface of carbon fiber material with zero valent silver (Ag) via chemical deposition. DNT detection was conducted electrochemically in aqueous media of pH 6.0. The cyclic voltammetric oxidation of DNT is diffusion controlled with detection sensitivity increasing with Ag loading of the electrode. Nevertheless, kinetic study given by Tafel slope and transfer coefficient (0.03 and 0.22 respectively) indicated slowly to moderate chemical reaction. The only oxidation product is benzoic acid, which suggests that the difference in performance of Ag/C electrode compared to other available materials is directly ascribable to the electrode fabricated in this study. Detection limit of DNT was 5 mu M with the electrode showing no signs of degradation after several cycles, and supported by surface behavior of characterized Ag/C electrode.Electrochimica Acta 04/2013; 88:832-838. DOI:10.1016/j.electacta.2012.10.068 · 4.09 Impact Factor
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ABSTRACT: Hydrous (or ) oxide. films produced on platinum in acid at room temperature usually give rise to two reduction peaks, in addition to the monolayer oxide response, on a negative sweep extending to about 0V. This has been attributed to the presence of two hydrous oxide components (designated as HO1 and HO2) in the film. It was confirmed in the present work that under more severe conditions, 3.0 m H2SO4 at 60C, an additional, quite significant, peak — apparently due to the presence of a further hydrous oxide component (HO3) — may be observed. The approximate peak maximum potential values (RHE scale) were 0.4 V (HO1), 0.2 V (HO2) and 0.0 V (HO3); the E p values are given here only as a guide: the processes involved occur under very irreversible conditions and the values vary with factors such as sweep rate, film thickness, temperature, etc. The differences in behaviour between these components is assumed to be due to factors such as the degree of aggregation and compactness in different regions of the gel-type, amorphous deposit. A brief account is given of the increasing evidence from different laboratories of unusual responses for platinum electrodes in aqueous acid solution.Journal of Applied Electrochemistry 05/1996; 26(6):593-601. DOI:10.1007/BF00253457 · 2.15 Impact Factor