1921. Impedimetric detection of histamine using PEDOT:PSS-based organic electrochemical sensor for precision animal agricultureHuiwen Bai, Kateryna Vyshniakova, Egon Pavlica, Victor Marco Rocha Malacco, Alexandros Yiannikouris, Thirupathi Reddy Yerramreddy, Richard M. Voyles, Shawn S. Donkin, Robert A. Nawrocki, 2021, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Ključne besede: electrochemical impedance spectroscopy, mixed conduction
Objavljeno v RUNG: 07.06.2021; Ogledov: 2009; Prenosov: 37
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1922. |
1923. |
1924. Removal of copper from aqueous solutions with zeolites and possible treatment of exhaust materialsNataša Zabukovec Logar, Iztok Arčon, Janez Kovač, Margarita Popova, 2021, izvirni znanstveni članek Opis: The mechanism of Cu2+ loading into commercially available natural HEU-type and synthetic LTA-type zeolites for their
possible use in environmental processes, such as water and air treatment applications, was studied. Elemental analysis,
SEM/EDXS, XRD, XAS and XPS analyses revealed 4-fold coordination of Cu2+ cations with oxygen atoms in the pores, a
predominant location of copper atoms on the surface of crystallites and retained crystallinity of zeolites throughout the
processes. The post-treatment of Cu2+-loaded samples with HCl and/or NaCl solutions confirmed the predominantly
reversible sorption of copper on zeolites from aqueous solutions by ion-exchange mechanism and, therefore, excellent
regeneration possibilities for both types of zeolites. Furthermore, with the calcination of exhaust metal-loaded zeolites,
catalysts for total toluene oxidation reaction, as a model VOC pollutant, were obtained.
Ključne besede: Cu2+ ion exchange, Total toluene oxidation, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, Zeolite
Objavljeno v RUNG: 03.06.2021; Ogledov: 2037; Prenosov: 153
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1925. |
1926. Photo-Chemically-Deposited and Industrial Cu/ZnO/Al2O3 Catalyst Material Surface Structures During CO2 Hydrogenation to Methanol: EXAFS, XANES and XPS Analyses of Phases After Oxidation, Reduction, and ReactionMaja Pori, Iztok Arčon, Venkata Dasireddy, Blaž Likozar, 2021, izvirni znanstveni članek Opis: Industrial Cu/ZnO/Al2O3 or novel rate catalysts, prepared with a photochemical deposition method, were studied under functional CH3OH synthesis conditions at the set temperature (T) range of 240–350 °C, 20 bar pressure, and stoichiometric carbon dioxide/hydrogen composition. Analytical scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray adsorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods were systematically utilized to investigate the interfaces, measured local geometry, and chemical state electronics around the structured active sites of commercially available Cu/ZnO/Al2O3 material or synthesized Cu/ZnO. Processed Cu K-edge EXAFS analysis suggested that various Cu atom species, clusters, metallic fcc Cu, Cu oxides (Cu2O or CuO) and the Cu0.7Zn2 alloy with hexagonal crystalline particles are contained after testing. It was proposed that in addition to the model’s Cu surface area, the amount, ratio and dispersion of the mentioned bonded Cu compounds significantly influenced activity. Additionally, XPS revealed that carbon may be deposited on the commercial Cu/ZnO/Al2O3, forming the inactive carbide coating with Cu or/and Zn, which may be the cause of basicity’s severe deactivation during reactions. The selectivity to methanol decreased with increasing T, whereas more Cu0.7Zn2 inhibited the CO formation through reverse water–gas shift (RWGS) CO2 reduction.
Ključne besede: CH3OH synthesis, Cu/ZnO-based catalyst, XPS, XANES, EXAFS analyses, Catalyst selectivity and activity
Objavljeno v RUNG: 03.06.2021; Ogledov: 2309; Prenosov: 0
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1927. Laser ablation-single-particle-inductively coupled plasma mass spectrometry as a multimodality bioimaging tool in nano-based omicsDino Metarapi, Johannes Teun van Elteren, Martin Šala, Katarina Vogel-Mikuš, Iztok Arčon, Vid Simon Šelih, Mitja Kolar, Samo B. Hočevar, 2021, izvirni znanstveni članek Opis: Advanced data processing and visualization techniques were applied to laser ablation-single particleinductively
coupled plasma mass spectrometry (LA-sp-ICPMS) data obtained from imaging of roots of
sunflower (Helianthus annuus L.) which were exposed to ionic silver (Ag+). Highly multiplexed images with
tissue level resolution were generated, showing the uptake and transformation of Ag+ to silver
nanoparticles (AgNPs) in whole root cross-sections, and revealing that the size of biosynthesized AgNPs is
predisposed by the reducing power of particular root compartments. Various Ag+ and AgNP visualization
strategies are shown with special emphasis on spatially resolved information associated with the number
and spherical-equivalent size of individual AgNPs in user-selected root cross-sectional regions, including
statistical analysis of the AgNP distribution. Normally, this multimodality information can only be obtained
by combining the results of techniques from several complementary platforms.
Ključne besede: Laser ablation, Ag XANES, bioimaging
Objavljeno v RUNG: 03.06.2021; Ogledov: 2151; Prenosov: 50
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1928. Spremljanje kemijskih procesov na atomskem nivoju v živo z rentgensko absorpcijsko spektrometrijoIztok Arčon, 2021, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Skokovit razvoj izjemno svetlih sinhrotronskih virov rentgenske in ultravijolične svetlobe v zadnjih letih je odprl nove možnosti za raziskave snovi na atomskem oziroma molekularnem nivoju, brez katerih si ne moremo predstavljati razvoja in sinteze novih funkcionalnih nanostrukturnih materialov z želenimi lastnostmi. V predavanju bodo predstavljene možnosti, ki jih nudi rentgenska absorpcijska spektroskopija s sinhrotronsko svetlobo pri karakterizacij različnih funkcionalnih nano-materialov v živo med njihovim delovanjem. Z metodama operando mikro-XANES in EXAFS lahko sledimo spremembam valenčnih stanj in lokalnih struktur izbranih elementov npr. v materialih za shranjevanje energije ali v različnih (foto)katalizatorjih, med kemičnimi reakcijami pri nadzorovanih reakcijskih pogojih, s čimer dobimo vpogled v dinamične funkcionalne lastnosti in mehanizme delovanja teh materialov. Novi sinhrotronski viri svetlobe odpirajo tudi možnosti kombinacije rentgenske spektroskopije in mikroskopije z ločljivostjo do nekaj deset nanometrov, s čimer lahko ključno prispevajo tudi k razumevanju mehanizmov zajemanja, transporta, akumulacije in kompleksacije kovinskih kationov na sub-celičnem nivoju v različnih tkivih rastlin, ki te polutante (hiper)akumulirajo in jih s tem prenašajo v prehranjevalno verigo.
Ključne besede: rentgenska absorpcijska spektroskopija, operando XAS, strukturna analiza materialov
Objavljeno v RUNG: 03.06.2021; Ogledov: 2066; Prenosov: 54
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1929. |
1930. Neznanka, ki na odgovor še čaka2021, intervju Opis: Vprašanje, kako in kje nastajajo kozmični delci ekstremnih energij, je odprto že več kot petdeset let. Med najverjetnejšimi kraji njihovega nastanka sodijo aktivna galaktična jedra; to so središča galaksij, v katerih se skrivajo črne luknje, ki požirajo snov iz okolice. V raziskavah mednarodne kolaboracije Pierre Auger sodelujejo tudi slovenski raziskovalci z Univerze v Novi Gorici in Instituta Jožef Stefan.
Ključne besede: kozmični delci ekstremnih energij, aktivna galaktična jedra, observatorij Pierre Auger, observatorij Cherenkov Telescope Array, CTA
Objavljeno v RUNG: 02.06.2021; Ogledov: 2480; Prenosov: 0
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