61. Conclusively Addressing the CoPc Electronic Structure: A Joint Gas- Phase and Solid-State Photoemission and Absorption Spectroscopy StudyTeng Zhang, I.E. Brumboiu, Valeria Lanzillotto, J. Lüder, C. Grazioli, Erika Giangrisostomi, R. Ovsyannikov, Y. Sassatelli, Ieva Bidermane, Monica de Simone, Marcello Coreno, Barbara Ressel, Matija Stupar, Maddalena Pedio, Petra Rudolf, Barbara Brena, Carla Puglia, 2017, izvirni znanstveni članek Ključne besede: Cobalt Phtalocyanine, photoemission spectroscopy, gas phase, solid state
Objavljeno v RUNG: 07.02.2018; Ogledov: 5963; Prenosov: 0
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62. New strategy for magnetic gas sensingRoberta Ciprian, Piero Torelli, Angelo Giglia, B Gobaut, Barbara Ressel, Janez Štupar, Matija Stupar, Antonio Caretta, Giovanni De Ninno, Tommaso Pincelli, Barbara Casarin, Ganesh Adhikari, G Sberviglieri, C Baratto, Marco Malvestuto, 2016, izvirni znanstveni članek Ključne besede: hybrid nanostructures, sensor, absorption spectroscopy
Objavljeno v RUNG: 05.02.2018; Ogledov: 5578; Prenosov: 0
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64. Design of a highly photocatalytically active ZnO/CuWO4 nanocompositeSaim Emin, Matjaž Valant, 2017, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: We report the synthesis, photocatalytic activity and mechanistic study of a novel heterostructure (HTS) with an efficient charge separation. A ZnO/CuWO4 HTS material is reported for the first time. The nanocomposite (NC) consists of CuWO4 nanoparticles (ca. 200-400 nm) decorated with ZnO nanorods (ca. 30 nm, 100 nm length) and is shown to be a highly active photocatalyst for decomposition of model contaminants including methyl orange and terephthalic acid. The ZnO/CuWO4 interface is shown to be the key for controlling the enhanced activity of the composite material. Transient absorption spectroscopy studies demonstrated that a photoinduced charge transfer across the ZnO/CuWO4 interface increased electron-hole lifetime by 3 orders of magnitude, from < 20 s in ZnO to 30 ms in the ZnO/CuWO4 NC sample. Our findings show that through interface design efficient HTS materials can be prepared for a wide range of photocatalytic applications.
Ključne besede: CuWO4, nanocomposite, transient absorption spectroscopy
Objavljeno v RUNG: 28.08.2017; Ogledov: 6899; Prenosov: 0
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65. Atomic-level mechanisms of magnesium oxidationSandra Gardonio, Mattia Fanetti, Matjaž Valant, Dmytro Orlov, 2016, objavljeni znanstveni prispevek na konferenci Opis: Magnesium has been recently becoming an increasingly popular material for various applications. However, excessive chemical reactivity, and oxidation rate in particular, is a major obstruction on the way of Mg to become widely adopted. A significant problem causing the lack of Mg reactivity control is insufficient understanding of mechanisms involved in the oxidation of magnesium surface. Herewith we present the investigation of atomic-level mechanisms of oxidation initiation and propagation in pure Mg. Namely, X-ray photoelectron spectroscopy at synchrotron Elettra was used as a surface sensitive direct method to determine the valence of Mg and O and the valence band states at the early stage of oxide formation over a principal, most densely packed, crystallographic plane (0001) in pure Mg. The mechanisms of oxygen adsorption on magnesium free surface followed by oxidation (i.e. initiation and kinetics of MgO formation) are clarified. Copyright © 2016 by The Minerals, Metals & Materials Society. All rights reserved.
Ključne besede: Magnesium, Oxidation, Synchrotron radiation, X-ray photoelectron spectroscopy
Objavljeno v RUNG: 25.08.2017; Ogledov: 6663; Prenosov: 0
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66. Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type AnalysisMaryline Pflieger, Petra Makorič, Manca Kovač Viršek, Špela Koren, 2017, pregledni znanstveni članek Opis: Plastic resin pellets, categorized as microplastics (≤5 mm in diameter), are small granules that can be unintentionally released to the
environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and
on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might
consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the
hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid
determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets,
analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets
by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy.
The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main
metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes
a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.
Ključne besede: Environmental Sciences, Issue 125, Microplastics, resin pellets, pesticides, persistent organic pollutants, organochlorine pesticides, dichlorodiphenyltrichloroethane, endosulfan, hexachlorocyclohexane, lindane, Fourier transform infrared spectroscopy, pressurized fluid extractor
Objavljeno v RUNG: 10.07.2017; Ogledov: 6295; Prenosov: 0 |
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69. Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasersSteffen Eich, Jurij Urbančič, 2014, izvirni znanstveni članek Opis: Time- and angle-resolved photoemission spectroscopy (trARPES) using femtosecond extreme ultraviolet high harmonics has recently emerged as a powerful tool for investigating ultrafast quasiparticle dynamics in correlated-electron materials. However, the full potential of this approach has not yet been achieved because, to date, high harmonics generated by 800 nm wavelength Ti:Sapphire lasers required a trade-off between photon flux, energy and time resolution. Photoemission spectroscopy requires a quasi-monochromatic output, but dispersive optical elements that select a single harmonic can significantly reduce the photon flux and time resolution. Here we show that 400 nm driven high harmonic extreme-ultraviolet trARPES is superior to using 800 nm laser drivers since it eliminates the need for any spectral selection, thereby increasing photon flux and energy resolution to <150 meV while preserving excellent time resolution of about 30 fs.
Ključne besede: angle-resolved photoemission spectroscopy, ARPES, high harmonic generation, ultrafast surface science
Objavljeno v RUNG: 20.04.2017; Ogledov: 6984; Prenosov: 0
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70. The mechanism of Li2S activation in lithium-sulfur batteries: Can we avoid the polysulfide formation?Alen Vižintin, Laurent Chabanne, Elena Tchernychova, Iztok Arčon, Lorenzo Stievano, Giuliana Aquilanti, Markus Antonietti, Tim-Patric Fellinger, Robert Dominko, 2017, izvirni znanstveni članek Opis: Electrochemical reactions in the LieS batteries are considered as a multistep reaction process with at least
2e3 equilibrium states. Here we report a possibility of having a conversion of Li2S into sulfur without
detectible formation of polysulfides. That was confirmed by using a novel material system consisting of
carbon coated Li2S particles prepared by carbothermal reduction of Li2SO4. Two independent in operando
measurements showed direct oxidation of Li2S into sulfur for this system, with almost negligible formation
of polysulfides at potentials above 2.5 V vs. Li/Liþ. Our results link the diversity of first charge profiles in the
literature to the Li2S oxidation mechanism and show the importance of ionic wiring within the material.
Furthermore, we demonstrate that the Li2S oxidation mechanism depends on the relative amount of
soluble sulfur in the electrolyte. By controlling the type and the amount of electrolyte within the encapsulating
carbon shell, it is thereby possible to control the reaction mechanism of Li2S activation.
Ključne besede: Lithium-sulfur batteries
Li2S active material
XAS
UV/Vis spectroscopy
Li2S activation
Objavljeno v RUNG: 03.03.2017; Ogledov: 7237; Prenosov: 0
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