311 research outputs found

    WPlYW GIElD sWIATOWYCH NA GloWNE INDEKSY GIElDOWE W POLSCE

    Get PDF
    Autor porownal 13 indeksow gieldowych rynku amerykanskiego, brytyjskiego oraz niemieckiego i okreslil ich wplyw na indeksy WIG i WIG20. Analiza pokazala, iz najwieksze znaczenie dla indeksow warszawskich mialy indeksy brytyjskie FTSE100 i FTSE250 oraz niemiecki DAX. Na relacje te wplynal tez kryzys rosyjski i amerykanski oraz wejscie Polski do UE.indeksy gieldowe, miedzynarodowy przeplyw kapitalu, globalizacja

    Photoelectrolytic oxidation of organic species at mesoporous tungsten trioxide film electrodes under visible light illumination

    Get PDF
    Operation of a photoelectrolyser fitted with a semitransparent semiconducting WO3 film photoanode is described. Due to its band-gap energy of 2.5eV, the photoresponse of the WO3 electrode extends into the blue part of the visible spectrum up to 500nm. The WO3 photoanode exhibits particularly high incident photon-to-current efficiencies for the oxidation of several organic species with the maximum occurring at ca. 400nm. Experiments conducted under simulated AM 1.5 solar illumination demonstrated efficient photodegradation of a variety of organic chemicals including small organic molecules as well as EDTA and anthraquinonic Acid Blue 80 dye. Although, due to the inherent mass transport limitations, the described device appears best suited to the treatment of industrial wastewater containing from 100ppm to few gL−1 of impurities, almost complete removal of organic carbon was observed in several photoelectrolysis runs. This is apparently associated with the concomitant photooxidation of sulphate-based supporting electrolyte resulting in the formation of a powerful chemical oxidant-persulphat

    Réduction Electrochimique du Bioxyde de Carbone en Solution Aqueuse

    Get PDF
    The reduction of carbon dioxide requires a substantial input of energy or a high energy reductant. Among possible energy sources which may be used to drive this reaction are electricity and light. First approaches to the electrochemical reduction of carbon dioxide in aqueous solutions are as old as the very beginning of interest in electrochemical processes. During several years, the cathodic reduction of carbon dioxide appeared as a highly irreversible reaction, restricted to the formation of formic acid. As will be shown in the present article, these views are to be re-examined in the light of the results of recent studies, showing that several electrode materials enable the reduction of carbon dioxide to occur with small or moderate overvoltages and to yield a large variety of products

    Commentaire: Pourquoi les Expériences de «Fusion Froide» de Deutérium Sont-elles Si Difficiles à Reproduire?

    Get PDF
    The particular conditions of the experiments described by Fleischmann and Pons, relative to “cold nuclear fusion” are examined. The possible role played by the platinum anode and the alkaline LiOD solution is discussed. A series of less expected electrochemical reactions leading to a possible lithium deposit (incorporation) on/to the palladium cathode are considered

    Electrochemical Measurements on Palladium Cathodes in LiOD/D2O Solutions related to the «Cold Fusion Experiments»

    Get PDF
    The current-voltage behaviour of palladium electrodes, polarized in an electrolysis cell filled up with a diluted solution of lithium deuteroxide in heavy water, is shown to be strongly influenced by the impurities co-depositing at the cathode. Among the impurities, identified on the surface of palladium at the end of the electrolyses, lead and especially zinc cause the shift of the electrode potential making possible lithium deposition and lithium deuteride formation. Some expected interactions of these compounds are discussed

    Study of the synergistic effect of 2-methoxy-4-formylphenol and sodium molybdenum oxide on the corrosion inhibition of 3CR12 ferritic steel in dilute sulphuric acid

    Get PDF
    The synergistic effect of the corrosion inhibition properties of 2-methoxy-4-formylphenol and sodium molybdenum oxide on the electrochemical property of 3CR12 ferritic stainless steel in 2M H2SO4 acid solution was assessed through coupon analysis, potentiodynamic polarization technique, IR spectroscopy and micro-analytical technique. Experimental data showed the combined admixture effectively inhibited the steel corrosion at the concentrations analyzed with a maximum inhibition efficiency of 94.47% and 89.71% from coupon analysis and potentiodynamic polarization due to the electrochemical action and inhibition of the steel by the ionized molecules of the inhibiting compound which influenced the mechanism of the redox reactions responsible to corrosion and surface deterioration. Results from corrosion thermodynamic calculations showed chemisorption adsorption mechanism. Infrared spectroscopic images exposed the functional groups of the molecules involved for the corrosion inhibition reaction. Micro-analytical images showed sharp contrast in surface morphology between the inhibited and corroded test specimens under study. Cracks, intergranular and pitting corrosion in addition to severe surface deterioration was observed in the uninhibited samples. Inhibitor adsorption fits the Langmuir isotherm mode

    The electronic structure of iridium oxide electrodes active in water splitting

    Get PDF
    Iridium oxide based electrodes are among the most promising candidates for electrocatalyzing the oxygen evolution reaction, making it imperative to understand their chemical/electronic structure. However, the complexity of iridium oxide's electronic structure makes it particularly difficult to experimentally determine the chemical state of the active surface species. To achieve an accurate understanding of the electronic structure of iridium oxide surfaces, we have combined synchrotron-based X-ray photoemission and absorption spectroscopies with ab initio calculations. Our investigation reveals a pre-edge feature in the O K-edge of highly catalytically active X-ray amorphous iridium oxides that we have identified as O 2p hole states forming in conjunction with IrIII. These electronic defects in the near-surface region of the anionic and cationic framework are likely critical for the enhanced activity of amorphous iridium oxides relative to their crystalline counterparts

    Modification des polymères conducteurs avec de petites particules métalliques; propriétés des films de polypyrrole et de polyaniline platines

    Get PDF
    The properties of two π-conjugated conducting polymers, polypyrrole, and polyaniline, modified with small amounts of Pt, have been investigated. Both polymers were prepared by electrochemical (cyclic voltammetric) polymerization in the form of thin films (less than 1 μm for polypyrrole, ca. 50-μm thick for polyaniline). It is shown that incorporation, via electrodeposition, of small amount of dispersed Pt particles, inside the polymer film, leads to radical change of its properties. Thus, the polypyrrole film electrode containing ca. 200 μg · cm-2 of Pt exhibits remarkably stable electrocatalytic activity towards anodic oxidation of an important fuel cell reactant – CH3OH. In contrast with the bulk Pt metal or the Pt dispersed on other supports, a polypyrrole/Pt composite does apparently not undergo poisoning, even in the course of prolonged oxidation runs. We show also that the incorporation of Pt microparticles, into several tens of μm thick polyniline films, results in a large enhancement of their redox switching rate between isolating and conducting states and vice versa
    corecore