21. Nitroreductase-sensitive fluorescent covalent organic framework for tumor hypoxia imaging in cellsTina Škorjanc, Dinesh Shetty, Sushil Kumar, Damjan Makuc, Gregor Mali, Janez Volavšek, Martina Bergant Marušič, Matjaž Valant, 2023, izvirni znanstveni članek Ključne besede: covalent organic frameworks, imaging, hypoxia, fluorescence, cancer cells Objavljeno v RUNG: 17.05.2023; Ogledov: 1716; Prenosov: 18 Celotno besedilo (1,55 MB) Gradivo ima več datotek! Več... |
22. Stable seawater oxidation with a self-healing oxygen-evolving catalystXiaojian Zhang, Chao Feng, Zeyu Fan, Beibei Zhang, Yequan Xiao, Andraž Mavrič, Nadiia Pastukhova, Matjaž Valant, Yi-Fan Han, Yanbo Li, 2023, izvirni znanstveni članek Opis: Direct seawater electrolysis is key to massive hydrogen fuel production without the depletion of precious freshwater resources and the need for high-purity electrolytes. However, the presence of high-concentration chloride ions (Cl−) and alkaline-earth metal ions (Mg2+, Ca2+) poses great challenges to the stability and selectivity of the catalysts for seawater splitting. Here, we demonstrate a self-healing oxygen evolution reaction (OER) catalyst for long-term seawater electrolysis. By suppressing the competitive chlorine evolution reaction and precipitating the alkaline-earth metal ions through an alkaline treatment of the seawater, stable seawater oxidation is achieved owing to the self-healing ability of the borate-intercalated nickel–cobalt–iron oxyhydroxides (NiCoFe-Bi) OER catalyst under highly-alkaline conditions. The self-healing NiCoFe-Bi catalyst achieves stable seawater oxidation at a large current density of 500 mA cm−2 for 1000 h with near unity Faraday efficiency. Our results have demonstrated strong durability and high OER selectivity of the self-healing catalyst under harsh conditions, paving the way for industrial large-scale seawater electrolysis. Ključne besede: chemistry, electrocatalysis, seawater oxidation, oxygen evolution reaction Objavljeno v RUNG: 08.05.2023; Ogledov: 1739; Prenosov: 5 Povezava na datoteko Gradivo ima več datotek! Več... |
23. Efficiency of the grid energy storage technology based on iron-chloride material cycleUroš Luin, doktorska disertacija Opis: Future high-capacity energy storage technologies are crucial for a highly renewable energy mix, and their mass deployment must rely on cheap and abundant materials, such as iron chloride. The iron chloride electrochemical cycle (ICEC), suitable for long-term grid energy storage using a redox potential change of Fe2+/Fe, involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial maximizing the energy efficiency of the electrolysis process. The thesis presents a study of the influence of electrolysis parameters on energy efficiency, performed in an industrial-type electrolyzer system. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency as a function of current density. The contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ±3 % was achieved using
2.5 mol dm-3 FeCl2 solution at 70 °C and a current density of 0.1 kA m-2.
In terms of the energy input per Fe mass, this means 1.88 Wh g-1. The limiting energy input per mass of the Fe-deposit, calculated by extrapolating experimental results toward Eocell potential, was found to be 1.76 Wh g-1. For optimal long-duration electrolysis efficiency and performance, the optimal catholyte concentration range is
1-2 mol dm-3 FeCl2. We performed in situ X-ray absorption spectroscopy experimental studies to validate theoretical conclusions from literature related to the population and structure of Fe-species in the FeCl2 (aq) solution at different concentrations (1 - 4 mol dm-3) and temperatures (25 - 80 °C). This revealed that at low temperature and low FeCl2 concentration, the octahedral first coordination sphere around Fe is occupied by one Cl ion at a distance of 2.33 (±0.02) Å and five H2O at a distance of 2.095 (±0.005) Å. The structure of the ionic complex gradually changes with an increase in temperature and/or concentration. The apical H2O is substituted by a Cl ion to yield a neutral Fe[Cl2(H2O)4]0. The transition from the charged Fe[Cl(H2O)5]+ to the neutral Fe[Cl2(H2O)4]0 causes a significant drop in the solution conductivity, which well correlates with the existing state-of-the-art conductivity models. An additional steric impediment of the electrolytic cell is caused by the predominant neutral species present in the catholyte solution at high concentration. This correlates with poor electrolysis performance at a very high catholyte concentration (4 mol dm-3 FeCl2), especially at high current densities (> 1 kA m-2). The neutral Fe[Cl2(H2O)4]0 complex negatively affects the anion exchange membrane ion (Cl-) transfer and lowers the concentration of electroactive species (Fe[Cl(H2O)5]+) at the cathode surface. The kinetics of hydrogen evolution from the reaction between Fe powder and HCl acid was studied under the first-order reaction condition. The activation energy was determined to be 55.3 kJ mol-1. Ključne besede: ICEC, Power-to-Solid, energy storage, hydrogen, ferrous chloride, electrolysis, Fe deposition, efficiency, XAS, structure and population, ionic species, ion association, conductivity Objavljeno v RUNG: 18.04.2023; Ogledov: 2128; Prenosov: 32 (1 glas) Celotno besedilo (4,34 MB) |
24. Non-covalent ligand-oxide interaction promotes oxygen evolutionQianbao Wu, Junwu Liang, Mengjun Xiao, Chang Long, Lei Li, Zhenhua Zeng, Andraž Mavrič, Xia Zheng, Jing Zhu, Matjaž Valant, 2023, izvirni znanstveni članek Opis: Strategies to generate high-valence metal species capable of oxidizing water often employ composition and coordination tuning of oxide-based catalysts, where strong covalent interactions with metal sites are crucial. However, it remains unexplored whether a relatively weak “non-bonding” interaction between ligands and oxides can mediate the electronic states of metal sites in oxides. Here we present an unusual non-covalent phenanthroline-CoO2 interaction that substantially elevates the population of Co4+ sites for improved water oxidation. We find that phenanthroline only coordinates with Co2+ forming soluble Co(phenanthroline)2(OH)2 complex in alkaline electrolytes, which can be deposited as amorphous CoOxHy film containing non-bonding phenanthroline upon oxidation of Co2+ to Co3+/4+. This in situ deposited catalyst demonstrates a low overpotential of 216 mV at 10 mA cm−2 and sustainable activity over 1600 h with Faradaic efficiency above 97%. Density functional theory calculations reveal that the presence of phenanthroline can stabilize CoO2 through the non-covalent interaction and generate polaron-like electronic states at the Co-Co center. Ključne besede: water oxidation, cobalt hydroxide, ligand-metal interactions Objavljeno v RUNG: 23.02.2023; Ogledov: 2315; Prenosov: 19 Celotno besedilo (1,77 MB) |
25. Silica coated ▫$Bi_2Se_3$▫ topological insulator nanoparticles : an alternative route to retain their optical properties and make them biocompatibleBlaž Belec, Nina Kostevšek, Giulia Della Pelle, Sebastjan Nemec, Slavko Kralj, Martina Bergant Marušič, Sandra Gardonio, Mattia Fanetti, Matjaž Valant, 2023, izvirni znanstveni članek Ključne besede: topological insulator, bismuth selenide, photo-thermal materials, biocompatibility, nanoparticles Objavljeno v RUNG: 22.02.2023; Ogledov: 2722; Prenosov: 6 Celotno besedilo (8,09 MB) Gradivo ima več datotek! Več... |
26. Life cycle assessment of black and greywater treatment solutions for remote and sensitive areasAndreea Oarga-Mulec, Janez Turk, Petra Gerbec, Petter D. Jenssen, Katja Malovrh Rebec, Matjaž Valant, 2023, izvirni znanstveni članek Ključne besede: life cycle assessment, sanitation systems, sustainability, remote areas, circular economy Objavljeno v RUNG: 20.02.2023; Ogledov: 2265; Prenosov: 7 Celotno besedilo (2,06 MB) Gradivo ima več datotek! Več... |
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28. Iron phosphide thin films for electrocatalytic H2 generation and water remediation studies : abstractTakwa Chouki, Manel Machreki, Jelena Topic, Lorena Butinar, Plamen Stefanov, Erika Jež, Jack S Summers, Matjaž Valant, Aaron Fait, Saim Emin, 2022, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: Iron phosphide thin films
H2 generation
water remediation Objavljeno v RUNG: 10.02.2023; Ogledov: 1589; Prenosov: 0 Gradivo ima več datotek! Več... |
29. V-ORAL17c: Cationic Covalent Organic Polymer for Bacterial Cell Detection by Electrochemical Impedance SpectroscopyTina Skorjanc, Andraz Mavric, Mads Nybo Sorensen, Gregor Mali, Changzhu Wu, Matjaž Valant, 2022, objavljeni znanstveni prispevek na konferenci Ključne besede: Electrochemical impedance spectroscopy, polymers, Menshutkin reaction, porphyrin, sensor Objavljeno v RUNG: 30.11.2022; Ogledov: 2838; Prenosov: 0 Gradivo ima več datotek! Več... |
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