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42. Effect of the Morphology of the High-Surface-Area Support on the Performance of the Oxygen-Evolution Reaction for Iridium NanoparticlesLeonard Moriau, Marjan Bele, Živa Marinko, Francisco Ruiz-Zepeda, Gorazd Koderman, Martin Šala, Angelija Kjara Šurca, Janez Kovač, Iztok Arčon, Primož Jovanovič, Nejc Hodnik, Luka Suhadolnik, 2021, izvirni znanstveni članek Opis: The development of affordable, low-iridium-loading,
scalable, active, and stable catalysts for the oxygen-evolution
reaction (OER) is a requirement for the commercialization of
proton-exchange membrane water electrolyzers (PEMWEs).
However, the synthesis of high-performance OER catalysts with
minimal use of the rare and expensive element Ir is very challenging
and requires the identification of electrically conductive and stable
high-surface-area support materials. We developed a synthesis
procedure for the production of large quantities of a nanocomposite
powder containing titanium oxynitride (TiONx) and Ir.
The catalysts were synthesized with an anodic oxidation process
followed by detachment, milling, thermal treatment, and the
deposition of Ir nanoparticles. The anodization time was varied to grow three different types of nanotubular structures exhibiting different lengths and wall thicknesses and thus a variety of properties. A comparison of milled samples with different degrees of nanotubular clustering and morphology retention, but with identical
chemical compositions and Ir nanoparticle size distributions and dispersions, revealed that the nanotubular support morphology is
the determining factor governing the catalyst’s OER activity and stability. Our study is supported by various state-of-the-art
materials’ characterization techniques, like X-ray photoelectron spectroscopy, scanning and transmission electron microscopies, Xray powder diffraction and absorption spectroscopy, and electrochemical cyclic voltammetry. Anodic oxidation proved to be a very suitable way to produce high-surface-area powder-type catalysts as the produced material greatly outperformed the IrO2 benchmarks
as well as the Ir-supported samples on morphologically different TiONx from previous studies. The highest activity was achieved for the sample prepared with 3 h of anodization, which had the most appropriate morphology for the effective removal of oxygen
bubbles. Ključne besede: electrocatalysis, oxygen-evolution reaction, TiONx-Ir powder catalyst, iridium nanoparticles, anodic oxidation, morphology−activity correlation Objavljeno v RUNG: 04.01.2021; Ogledov: 2757; Prenosov: 0 Gradivo ima več datotek! Več... |
43. Spremljanje, ugotavljanje in zagotavljanje kakovosti: poročilo za študijsko leto 2019/2020 : Univerza v Novi Gorici. : poročilo za študijsko leto 2019/2020 : Univerza v Novi Gorici.Iztok Arčon, Jana Beguš, Blaž Belec, Martina Bergant Marušič, Lorena Butinar, IMRE CIKAJLO, Saša Dobričič, Sandra Gardonio, Renata Kop, Martin Knez, Boštjan Potokar, Branka Mozetič Vodopivec, Egon Pavlica, Samo Stanič, Tea Stibilj Nemec, Željko Oset, VERONIA Piccinini, Peter Purg, Arthur Stepanov, Aljaž Rener, Nives Štefančič, Ana Toroš, Tanja Urbančič, Vanesa Valentinčič, NIKA VODOPIVEC, elaborat, predštudija, študija Ključne besede: samoevalvacijsko poročilo Objavljeno v RUNG: 23.12.2020; Ogledov: 3571; Prenosov: 0 Gradivo ima več datotek! Več... |
44. Spremljanje, ugotavljanje in zagotavljanje kakovosti: : poročilo za študijsko leto 2019/2020 : Univerza v Novi Gorici, Fakulteta za znanosti o okoljuIztok Arčon, Blaž Belec, Marina Artico, Tea Stibilj Nemec, Maja Terčon, Matjaž Valant, Aljaž Rener, JANA BLEGUŠ, elaborat, predštudija, študija Ključne besede: samoevalvacijsko poročilo Objavljeno v RUNG: 23.12.2020; Ogledov: 2798; Prenosov: 66 Celotno besedilo (3,81 MB) |
45. Academic career routeIztok Arčon, vabljeno predavanje na konferenci brez natisa Opis: Early career scientists have developed a wealth of both generic and specialist skills opening a large number of possible career paths both within and beyond academic research. One of the problems that most PhD students, postdocs and other early career scientists find however is a significant lack of careers advice about the breadth of opportunities open to them both within academia and in commercial industry. The event will feature a number of speakers from a very diverse range of science careers, who will discuss their experiences and share advice on finding the best job opportunities. Ključne besede: academic career, generic skills, PhD students, post-doctoral fellows Objavljeno v RUNG: 02.11.2020; Ogledov: 2915; Prenosov: 0 Gradivo ima več datotek! Več... |
46. Temporal and spatial patterns of zinc and iron accumulation during barley (Hordeum vulgare L.) grain development. Journal of agricultural and food chemistry.Amelie Detterbeck, Paula Pongrac, Daniel Persson, Katarina Vogel-Mikuš, Mitja Kelemen, Primož Vaupetič, Primož Pelicon, Iztok Arčon, Søren Husted, Jan Kofod Shjoerring, Stephan Clemens, 2020, izvirni znanstveni članek Opis: Breeding and engineering of biofortified crops will benefit from a better understanding of bottlenecks controlling
micronutrient loading within the seeds. However, few studies have addressed the changes in micronutrient concentrations,
localization, and speciation occurring over time. Therefore, we studied spatial patterns of zinc and iron accumulation during grain
development in two barley lines with contrasting grain zinc concentrations. Microparticle-induced-X-ray emission and laser ablationinductively
coupled plasma mass spectrometry were used to determine tissue-specific accumulation of zinc, iron, phosphorus, and
sulfur. Differences in zinc accumulation between the lines were most evident in the endosperm and aleurone. A gradual decrease in
zinc concentrations from the aleurone to the underlying endosperm was observed, while iron and phosphorus concentrations
decreased sharply. Iron co-localized with phosphorus in the aleurone, whereas zinc co-localized with sulfur in the sub-aleurone. We
hypothesize that differences in grain zinc are largely explained by the endosperm storage capacity. Engineering attempts should be
targeted accordingly. Ključne besede: barley (Hordeum vulgare L.), biofortification, grain development, grain loading, LA-ICP-MS, μ-PIXE Objavljeno v RUNG: 20.10.2020; Ogledov: 2948; Prenosov: 0 Gradivo ima več datotek! Več... |
47. VELIKOKRAT NAS JE PRESENETILO, KAJ ATOMI DEJANSKO POČNEJO : IZTOK ARČONIztok Arčon, Nina Slaček, radijska ali televizijska oddaja, podkast, intervju, novinarska konferenca Opis: Razvoj novih materialov, nanotehnologije, molekularne biologije in še številnih drugih področij sodobnih znanosti je tesno povezan s podrobnim razumevanjem tega, kaj se dejansko dogaja na molekularnem oziroma atomskem nivoju. Za razvoj denimo novih nanostrukturnih materialov za baterije prihodnosti je nujno videti, kaj se v njih dejansko dogaja med samim delovanjem. To omogoča rentgenska absorpcijska spektroskopija s sinhrotronsko svetlobo.
»Ko z rentgenskim žarkom posvetimo na snov, iz atoma izbijemo elektron in ta odleti v okolico, se od nje odbija in nam na ta način sporoči, kaj se v njegovi okolici nahaja,« razlaga osnovni princip te metode prof. dr. Iztok Arčon.
Na ta način je mogoče pridobiti številne ključne podatke, ki pogosto na glavo postavijo predhodne domneve raziskovalcev. A za takšne raziskave je nujen sinhrotron. Tovrstnih pospeševalnikov ni veliko in merilni čas na sinhrotronu je potrebno pridobiti z vrhunsko zastavljenimi raziskavami. A tokratni gost Podob znanja, dr. Iztok Arčon, redni profesor na Univerzi v Novi Gorici, ima po zaslugi svojega znanstvenega dela na tem področju na široko odprta vrata, sodeluje pa raziskovalnimi skupinami z zelo različnih področij. Letos je za svoje dosežke prejel tudi Preglovo nagrado.
Foto: iz osebnega arhiva Iztoka Arčona Ključne besede: rentgenska absorpcijska spektroskopija, sinhrotronsko sevanje, raziskave nanomaterialov, Preglova nagrada 2020 Objavljeno v RUNG: 19.10.2020; Ogledov: 2884; Prenosov: 0 Gradivo ima več datotek! Več... |
48. X-ray absorption spectroscopy analysis: in situ, operando, in vivoIztok Arčon, 2020, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: X-ray absorption spectroscopy (XAS) is a powerful tool for characterisation of local structure and chemical state of selected elements in different new functional materials and biological or environmental samples. The XAS spectroscopy is based on extremely bright synchrotron radiation X-rays sources, which allow precise characterisation of bulk, nanostructured or highly diluted samples. With its two methods (XANES and EXAFS) it enables monitoring changes in valence states and local structures of constituent elements during chemical reactions under controlled reaction conditions, and it offers a possibility of a combination of X-ray spectroscopy and microscopy with sub-micron lateral resolution, crucial for analysis of biological samples on sub-cellular level. In this talk some typical examples of advanced XAS analysis will be presented. Ključne besede: X-ray absorption spectroscopy, EXAFS, XANES, in-situ, operando Objavljeno v RUNG: 17.10.2020; Ogledov: 3274; Prenosov: 0 Gradivo ima več datotek! Več... |
49. Structural and CO [sub] 2 capture properties of ethylenediamine-modified HKUST-1 metal-organic frameworkNika Vrtovec, Matjaž Mazaj, Gianpiero Buscarino, Angela Terracina, S. Agnello, Iztok Arčon, Janez Kovač, Nataša Zabukovec Logar, 2020, izvirni znanstveni članek Ključne besede: functionalization, modification, adsorption, extended X-ray absorption fine structure, materials Objavljeno v RUNG: 17.10.2020; Ogledov: 2801; Prenosov: 0 |
50. Spectroscopic insights into the electrochemical mechanism of rechargeable calcium/sulfur batteriesAntonio Scafuri, Romain Berthelot, Klemen Pirnat, Alen Vižintin, Jan Bitenc, Giuliana Aquilanti, Dominique Foix, Rémi Dedryvère, Iztok Arčon, Robert Dominko, Lorenzo Stievano, 2020, izvirni znanstveni članek Opis: Calcium batteries represent a promising alternative to lithium metal systems. The combination of the low redox potential and low cost and the energy-dense calcium anode (2073 mAh/cm3, similar to 2044 mAh/cm3 for Li) with appropriate low-cost cathode materials such as sulfur could produce a game-changing technology in several fields of applications. In this work, we present the reversible activity of a proof-of-concept Ca/S battery at room temperature, characterized by a surprising medium-term cycling stability with low polarization, promoted by the use of a simple positive electrode made of sulfur supported on an activated carbon cloth scaffold, and a state-of-the-art fluorinated alkoxyborate-based electrolyte. Insights into the electrochemical mechanism governing the chemistry of the Ca/S system were obtained for the first time by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The mechanism implies the formation of different types of soluble polysulfide species during both charge and discharge at room temperature, and the formation of solid CaS at the end of discharge. The reversible electrochemical activity is proven by the reformation of elemental sulfur at the end of the following charge. These promising results open the way to the comprehension of emerging Ca/S systems, which may represent a valid alternative to Mg/S and Li/S batteries. Ključne besede: Calcium/Sulfur Batteries
EXAFS, XANES Objavljeno v RUNG: 17.10.2020; Ogledov: 3072; Prenosov: 0 Gradivo ima več datotek! Več... |