1. XAS study of thermal and hydrothermal stability of two iron containing molecular sievesMojca Rangus, Iztok Arčon, Alojz Kodre, Tadeja Birsa Čelič, Jana Padežnik Gomilšek, Nataša Zabukovec Logar, 2010, final research report Found in: ključnih besedah
Keywords: rentgenska absorpcija, spektroskopija, Fe EXAFS
Published: 15.10.2013; Views: 5246; Downloads: 27
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2. Absolute determination of the X-ray absorption coefficient of barium in the L region using a liquid absorption cellAlojz Kodre, Jana Padežnik Gomilšek, Robert Hauko, Martin Šala, Iztok Arčon, 2013, original scientific article Found in: ključnih besedah
Keywords: barij, atomski absorpcijski presek, absorpcijski robovi L, EXAFS
Published: 15.10.2013; Views: 5992; Downloads: 190
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4. X-ray absorption spectroscopy and related techniquesIztok Arčon, Alojz Kodre, Jana Padežnik Gomilšek, 2004, original scientific article Abstract: In the extensive field of X-ray diagnostic techniques, nowadays mostly implemented on synchrotron X-ray sources, the X-ray absorption methods offer a relatively simple tool for structural analysis of materials. The advantage of the methods is the sensitivity to chemical species and the insensitivity to the long-range order. An overview of various detection techniques is given together with the discussion of accuracy of the method with regard to the spatial resolution and the possible contamination by intra-atomic contributions, the multielectron photoexcitations.
Found in: ključnih besedah
Keywords: X-žarki, absorpcija, EXAFS, XANES
Published: 10.07.2015; Views: 4039; Downloads: 23
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5. High-resolution X-ray absorption spectrometry of atomic vaporsIztok Arčon, Jana Padežnik Gomilšek, Alojz Kodre, Andrej Mihelič, 2004, original scientific article Abstract: A measurement of an x-ray absorption spectrum of a monatomic sample yields pure atomic absorption essential for the EXAFS (Extended X-ray Absorption FineStructure) analysis in cases of a weak structural signal. A construction of an absorption cell to contain vapor sample takes into account specific properties of the investigated element. Metal-vapor absorption cells for the elements K, zn, Rb, Cd, Cs, and Hg are presented and comments are made on the use of materials and the operating mechanisms of the cells.
Found in: ključnih besedah
Keywords: X-žarki, absorpcija, EXAFS, absorpcijske celice
Published: 10.07.2015; Views: 4289; Downloads: 24
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6. X-ray absorption spectroscopy analysis: in situ, operando, in vivoIztok Arčon, 2020, published scientific conference contribution abstract (invited lecture) Abstract: 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.
Found in: ključnih besedah
Keywords: X-ray absorption spectroscopy, EXAFS, XANES, in-situ, operando
Published: 17.10.2020; Views: 2220; Downloads: 0
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7. Spectroscopic insights into the electrochemical mechanism of rechargeable calcium/sulfur batteriesGiuliana Aquilanti, Jan Bitenc, Romain Berthelot, Antonio Scafuri, Alen Vižintin, Klemen Pirnat, Lorenzo Stievano, Robert Dominko, Iztok Arčon, Rémi Dedryvère, Dominique Foix, 13, original scientific article Abstract: 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.
Found in: ključnih besedah
Keywords: Calcium/Sulfur Batteries
EXAFS, XANES
Published: 17.10.2020; Views: 2124; Downloads: 0
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9. Removal of manganese in batch and fluidized bed systems using beads of zeolite a as adsorbentBojana Obradovic, Nataša Novak Tušar, Iztok Arčon, Janez Kovač, Mina Jovanovic, Nevenka Rajić, 2016, original scientific article Abstract: In this study the uptake capacity of Mn(II) ions by zeolite A beads was investigated for different initial Mn concentration (100e400 mg Mn dm^-3) in batch mode at 25e55 C. The obtained adsorption capacity varying from 30 to 50 mg Mn g^-1 demonstrated a high affinity of zeolite A towards Mn(II) present in solutions. Kinetic studies indicated the intra-particle diffusion as the rate limiting step up to 45 C with apparent diffusivities in the range (1.2e2.0) x 10^-13 m2 s^-1 and the activation energy of 21.9 kJ mol^-1, which implies strong interactions between the zeolite A and Mn ions. At 55 C ion-exchange became the rate limiting step. The adsorption isotherms were studied at 25 C showing that the Mn adsorption is the best described by the Langmuir model suggesting a homogenous zeolite surface. XPS analysis of the Mnloaded beads showed that there is no surface accumulation of Mn but an almost uniform Mn distribution inside zeolite A, whereas XANES and EXAFS suggested that the adsorption of Mn(II) was followed by the Mn(II) oxidation and oxide formation. Regeneration of the spent zeolite was examined in 8 adsorption/desorption cycles by a chelating Na2EDTA in a fluidized column. It has been found that zeolite A beads could be reused for at least 4 cycles with satisfactory Mn(II) adsorption efficiencies of about 70%.
Found in: ključnih besedah
Keywords: Zeolite A
Manganese
Adsorption kinetics
EXAFS/XANES
XPS
Published: 01.04.2016; Views: 4502; Downloads: 0
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10. Specific EXAFS tools in analysis of MoSI nanowiresAnton Meden, Alojz Kodre, Iztok Arčon, Jana Padežnik Gomilšek, Dragan Mihailović, 2006, original scientific article Abstract: Specific EXAFS tools in analysis of MoSI nanowires
Found in: ključnih besedah
Keywords: EXAFS, MoSI, nanocevke, struktura
Published: 17.05.2016; Views: 3618; Downloads: 17
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