1. Periodic anti-phase boundaries and crystal superstructures in ▫$PtCu_3$▫ nanoparticles as fuel cell electrocatalystsAna Rebeka Kamšek, Anton Meden, Iztok Arčon, Primož Jovanovič, Martin Šala, Francisco Ruiz-Zepeda, Goran Dražić, Miran Gaberšček, Marjan Bele, Nejc Hodnik, 2023, original scientific article Published in RUNG: 19.09.2023; Views: 1635; Downloads: 9
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2. Application of beam deflection spectrometry for the determination of iron species in passive samplers exposed to Southern Ocean ice : poster at International School of Quantum Electronics, 64th Course: Progress in Photoacoustic & Photothermal Phenomena, Erice - Sicily, October 16th-23rd, 2021Hanna Budasheva, Arne Bratkič, Martin Šala, Dorota Korte, Mladen Franko, 2021, unpublished conference contribution Published in RUNG: 02.12.2021; Views: 2372; Downloads: 46
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3. 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, original scientific article Abstract: 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.
Keywords: Laser ablation, Ag XANES, bioimaging
Published in RUNG: 03.06.2021; Views: 2913; Downloads: 51
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4. 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, original scientific article Abstract: 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.
Keywords: electrocatalysis, oxygen-evolution reaction, TiONx-Ir powder catalyst, iridium nanoparticles, anodic oxidation, morphology−activity correlation
Published in RUNG: 04.01.2021; Views: 3225; Downloads: 0
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5. Staranje nitrogvajakola pod vplivom sončne svetlobeAjda Delić, 2020, master's thesis Abstract: Nitrogvajakoli so rumeno obarvane spojine, ki prispevajo k absorpciji rjavega ogljika v ozračju. Na podnebje vplivajo z absorbiranjem svetlobe v bližnjem UV in vidnem delu spektra, saj po absorpciji sproščajo toploto, kar vodi v ogrevanje ozračja. Poleg tega imajo škodljiv vpliv tudi na ekosistem. Prisotnost v ozračju in njihovi mehanizmi nastanka so že raziskani, mehanizmi razpadanja v vodni fazi ozračja pa so malo znani. V tem delu smo raziskali, kako sončna svetloba vpliva na staranje nitrogvajakolov v ozračju. Z uporabo fotospektroskopije smo najprej proučili spektroskopske lastnosti vodnih raztopin gvajakola, 4-nitrogvajakola, 5-nitrogvajakola in dinitrogvajakola ter kako nanje vpliva pH. Preiskovani nitrogvajakoli v vidnem delu spektra močno absorbirajo le pri visokih pH, dinitrogvajakol pa zaradi nekoliko nižjega pKa absorbira tudi že pri rahlo kislih pH vrednostih. pH raztopin 4-nitrogvajakola in 5-nitrogvajakola različnih koncentracij smo pred fotolizo prilagodili na vrednost atmosferskih vod (pH okoli 5), nato pa smo jih izpostavili sončnemu simulatorju z močjo enega sonca. Produkte fotorazgradnje smo ločili in identificirali s tekočinsko kromatografijo sklopljeno s pretočnim spektrometrom in tandemskim masnim spektrometrom (LC-UV/Vis-MS/MS). Fotorazgradnja nitrogvajakolov poteka zelo počasi. Najdeni produkti imajo ohranjen aromatski obroč in eno ali več nitro skupin (dinitrogvajakol, 4-nitrokatehol). Zaključimo lahko, da so nitrogvajakoli v vodni fazi ozračja obstojni, absorbirajo v širokem območju pH vrednosti in s svojimi absorpcijskimi lastnostmi skupaj s produkti fotorazgradnje prispevajo k vplivu rjavega ogljika na podnebje.
Keywords: Rjavi ogljik, nitrogvajakol, fotorazpad, spektroskopske lastnosti, vpliv pH, identifikacija produktov, LC-UV/Vis-MS/MS
Published in RUNG: 03.06.2020; Views: 4551; Downloads: 134
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6. Electrochemical dissolution of iridium and iridium oxide particles in acidic media : transmission electron microscopy, electrochemical flow cell coupled to inductively coupled plasma mass spectrometry and X-ray absorption spectroscopy studyPrimož Jovanovič, Nejc Hodnik, Francisco Ruiz-Zepeda, Iztok Arčon, Barbara Jozinović, Milena Zorko, Marjan Bele, Martin Šala, Vid Simon Šelih, Samo B. Hočevar, Miran Gaberšček, 2017, original scientific article Abstract: Iridium based particles as the most promising proton exchange membrane electrolyser electrocatalysts were investigated
by transmission electron microscopy (TEM), and by coupling of electrochemical flow cell (EFC) with online inductively
coupled plasma mass spectrometer (ICP-MS). Additionally, a thin-film rotating disc electrode (RDE), an identical location transmission
and scanning electron microscopy (IL-TEM and IL-SEM) as well as an X-ray absorption spectroscopy (XAS) studies have
been performed. Extremely sensitive online time-and potential-resolved electrochemical dissolution profiles revealed that iridium
particles dissolved already well below oxygen evolution reaction (OER) potentials, presumably induced by iridium surface oxidation
and reduction processes, also referred to as transient dissolution. Overall, thermally prepared rutile type IrO2 particles (T-IrO2)
are substantially more stable and less active in comparison to as prepared metallic (A-Ir) and electrochemically pretreated (E-Ir)
analogues. Interestingly, under OER relevant conditions E-Ir particles exhibit superior stability and activity owing to the altered
corrosion mechanism where the formation of unstable Ir(>IV) species is hindered. Due to the enhanced and lasting OER performance,
electrochemically pre-oxidized E-Ir particles may be considered as the electrocatalyst of choice for an improved low temperature
electrochemical hydrogen production device, namely a proton exchange membrane electrolyser.
Keywords: Iridium Oxide Par-ticles, Electrochemical Dissolution of Iridium, Ir L3-edge XANES
Published in RUNG: 23.08.2017; Views: 4587; Downloads: 0
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7. Atomically resolved dealloying of structurally ordered Pt nanoalloy as an oxygen reduction reaction electrocatalystAndraž Pavlišič, Primož Jovanovič, Vid Simon Šelih, Martin Šala, Marjan Bele, Goran Dražić, Iztok Arčon, Samo B. Hočevar, Anton Kokalj, Nejc Hodnik, Miran Gaberšček, original scientific article Abstract: The positive effect of intermetallic ordering of platinum alloy nanoparticles on oxygen reduction reaction (ORR) activity has been well established. What is still missing is an understanding of selective leaching of the less noble metal from the ordered structure and its correlation to longterm ORR performance. Using a combination of kinetic Monte Carlo simulations and advanced characterization techniques, we provide unprecedented insight into dealloying of intermetallic PtCu3 nanoparticles a well-known binary alloy. Comparison of ordered and disordered samples with identical initial compositions and particle size distributions reveals an unexpected correlation: whereas the copper dealloying rates in the ordered and disordered counterparts are almost the same, in the ordered structure Pt atoms are surrounded by 15−30% more Cu atoms throughout all the stages of acid leaching. This more convenient Pt−Cu coordination explains the statistically significant increase of 23−37% in ORR activity of the ordered structure at all stages of alloy degradation.
Keywords: ORR activity, fuel cells, platinum alloy, nanoparticle stability, intermetallic ordering, kinetic Monte Carlo, dealloying, in situ ICP-MS
Published in RUNG: 27.09.2016; Views: 6401; Downloads: 0
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