Search results for "Redox"
showing 10 items of 619 documents
Amorphous semiconductor—electrolyte junction. Energetics at the a-WO3—electrolyte junction
1991
In order to elucidate the influence of thickness and amorphous structure on the kinetics of electron exchange with redox couples in solution, a critical re-examination of the energetics at the amorphous anodic WO3 films (a-WO3)—electrolyte junction has been performed, based on a recent theory of amorphous semiconductor (a-SC) Schottky barrier. The admittance study of the barrier performed in a large interval of electrode potential at changing frequency and film thickness allowed the determination of the energy levels as well as the distribution of localized electronic states within the mobility gap of the films. The new energetic picture derived is able to explain some features of the kinet…
Redox reactions in the Pt/TiO2–WO3/SiO2 planar system
2014
Abstract The thermal behavior of the titanium–tungsten adhesive layer (30–70 at.%) deposited on a SiO2 substrate followed by a thicker Pt layer was investigated. The resulting Pt/TiW/SiO2 planar system was annealed under air or vacuum. Morphological and chemical characterizations at different stages of the annealing, as a function of several parameters such as treatment atmosphere, annealing temperature and thickness of the Pt film were performed through surface science analyses. When annealing under air, even at mild temperature (773 K), the whole interlayer oxidizes while a low amount of tungsten diffuses through platinum film. This phenomenon is related to tungsten oxidation which acts a…
Abatement of 1,1,2,2-tetrachloroethane in water by reduction at silver cathode and oxidation at boron doped diamond anode in micro reactors
2012
The treatment of aqueous solutions of 1,1,2,2-tetrachloroethane was performed by anodic oxidation at boron doped diamond (BDD), cathodic reduction at silver and coupled processes. Experiments were performed in macro and micro reactors with an interelectrode distance lower than 100. μm. Drastically higher abatements of the chlorinated compound and current efficiencies were obtained in microdevices that, furthermore, allowed to perform the electrolyses with low cell voltages in the absence of supporting electrolyte. When reduction and oxidation processes were carried out simultaneously in the microreactor, a higher abatement of pollutants was obtained with the same amount of the passed charge…
Effective low temperature reduction of graphene oxide with vanadium(iii)
2014
Reduction of graphene oxide (GO) with vanadium(III) trichloride under various reaction conditions has been investigated. The results show that V(III) can be used as an efficient reducing agent for GO in aqueous solutions at low concentrations and in moderate temperatures under ambient conditions. The IR spectroscopy and X-ray photoelectron spectroscopy (XPS) show that the structure of the vanadium-reduced material is similar to reduced graphene oxide prepared using TiCl3 or hydrazine as a reducing agent. The electrical conductivity of the material is also similar in all cases. However, on the basis of the XPS results, vanadium-based reduction does not leave significant reductant impurities …
Design of highly efficient porous carbon foam cathode for electro-Fenton degradation of antimicrobial sulfanilamide
2021
Abstract This work investigated, for the first time, the potential of novel biomass derived carbon foam as a suitable and efficient electrocatalytic material (as cathode) for in-situ hydrogen peroxide (H2O2) production and its applicability in electro-Fenton (EF) approach for oxidizing organic pollutants. The carbon foam cathode was prepared by polymerization and carbonization of sucrose at high temperature. The as-prepared carbon foam consists of highly porous and extremely light structure with interconnected spherical cells. It exhibited excellent electrocatalytic properties such as high conductivity, relatively high redox current and several active-sites for producing oxidizing species, …
Ni alloy nanowires as high efficiency electrode materials for alkaline electrolysers
2021
Abstract The fabrication and characterization of nickel-alloy electrodes for alkaline electrolysers is reported. Three different alloys (Ni–Co, Ni–Zn and Ni–W) at different composition were studied in order to determine the optimum condition. Nanostructured electrodes were obtained by template electrodeposition into a nanoporous membrane, starting from aqueous solution containing the two elements of the alloy at different concentrations. Composition of alloys can be tuned by electrolyte composition and also depends on the difference of the redox potential of elements and on the presence of complexing agents in deposition bath. Electrochemical and electrocatalytic tests, aimed at establishin…
Electrochemical Reduction and Oxidation of Ruddlesden–Popper-Type La2NiO3F2 within Fluoride-Ion Batteries
2021
Within this article, it is shown that an electrochemical defluorination and additional fluorination of Ruddlesden–Popper-type La2NiO3F2 is possible within all-solid-state fluoride-ion batteries. St...
Characterization and Electrochemical Properties of Oxygenated Amorphous Carbon (a-C) Films
2016
Amorphous carbon (a-C) films with varying oxygen content were deposited by closed-field unbalanced magnetron sputtering with the aim to understand the effect of oxygen on the structural and physical properties of the films and subsequently correlate these changes with electrochemical properties. The a-C films were characterized by transmission electron microscopy, helium-ion microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and time-of-flight elastic recoil detection analysis. The electrochemical properties were studied by electrochemical impedance spectroscopy and cyclic voltammetry with several redox systems (Ru(NH3)62+/3+, Fe(CN)64−/3−, dopamine an…
Iron and lithium-iron alkyl phosphates as nanostructured material for rechargeable batteries
2018
Abstract Inorganic/organic hybrid materials composed by iron atoms bonded to an alkyl phosphate can be easily synthesized by mixing at 110 °C iron chlorides with tri-alkyl phosphates. Since structural information on these products are lacking and taking into account that lithium/iron organic hybrid materials are important in lithium ion battery technology we report here the physico-chemical characterization of different hybrid lithium/iron butylphosphates. These materials are characterized by the presence of elongated hexagonal crystals stable up to 315 °C. The insertion of lithium does not affect the local structure. Thanks to such structures the material can be electrochemically-cycled an…
Enhanced kinetics of hole transfer and electrocatalysis during photocatalytic oxygen evolution by cocatalyst tuning
2016
Understanding photophysical and electrocatalytic processes during photocatalysis in a powder suspension system is crucial for developing efficient solar energy conversion systems. We report a substantial enhancement by a factor of 3 in photocatalytic efficiency for the oxygen evolution reaction (OER) by adding trace amounts (∼0.05 wt %) of noble metals (Rh and Ru) to a 2 wt % cobalt oxide modified Ta3N5 photocatalyst particulate. The optimized system exhibited high quantum efficiencies (QEs) of up to 28 and 8.4% at 500 and 600 nm in 0.1 M Na2S2O8 at pH 14. By isolation of the electrochemical components to generate doped cobalt oxide electrodes, the electrocatalytic activity of cobalt oxide …