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2. Colloidal metal nanoparticles as a source for the growth of thin filmsSaim Emin, 2022, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: Synthesis of colloidal nanoparticles (NPs) which offer good colloidal stability is quite important for different applications like spin-coating, dip-coating etc. Having metallic nanoparticles in the form of stable suspension allow the generation of thin films with desired thicknesses. We will present the production of different classes of materials starting from colloidal metal NPs. An example will be given on the preparation of Fe2O3 and WO3 thin films which are used in photoelectrochemical oxidation of water (e.g. water splitting). Another transformation which involves metallic NPs include the preparation of MoSe2 and WSe2 thin films which is achieved in a tube furnace at elevated temperatures. Very recently, the use of metallic NPs were also extended for the preparation of transition metal carbides. We managed to produce W2C and WC phases starting from metallic W NPs. The details of this phase conversion will be discussed. The presentation will provide details on how transition metallic NPs can be used to prepare metal oxide, metal selenide and metal carbides.
Ključne besede: colloidal metal nanoparticles, thin films, water splitting
Objavljeno v RUNG: 16.01.2025; Ogledov: 961; Prenosov: 0
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3. Biotechnological recycling and recovery of metals from secondary raw materials through biogenic synthesis of nanoparticlesSvetlin Toshev, Alexandre Loukanov, Saim Emin, Seilichiro Nakabayashi, 2021, izvirni znanstveni članek Opis: The waste electrical and electronic equipment (WEEE) is an important secondary source for renewable extraction of valuable metals and raw materials.
The mineral biotechnologies are promising alternative to the current industrial chemical technologies for waste treatment, which are often accompanied with negative environmental impact. Here we report a systematic biotechnological strategy for recycling, recovering and extraction of metals from WEEE as biogenic formed nanoparticles. The process is based on two general steps – bioleaching (through autotrophic/heterotrophic bacteria), and extraction from the effluent as biosynthesised nanoscale materials. The obtained analytical data revealed that copper was bioleached in the form of nanoparticles, the efficiency being more than 90 %, which was the highest achieved value in comparison with the other metals. The recovered content of gold was less than 50 %, but the efforts for improvement of microbial leaching efficiency of Au are still in progress. The reported eco–friendly biotechnological approach enables proper implementation of new resource recovery–oriented recycling strategies with reduced risk of negative impact on nature.
Ključne besede: biotechnological recycling, secondary raw materials, nanoparticles
Objavljeno v RUNG: 10.01.2025; Ogledov: 565; Prenosov: 4
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4. Performance of copper - based catalysts for electrochemical CO2 reductionStefan Popović, 2023, doktorska disertacija Opis: The industrial era has brought a never-ending problem to
civilization through the emission of greenhouse gases (GHGs)
while extracting energy from fossil fuels for a variety of processes. Among different GHGs, carbon dioxide (CO2) stood out as one of the most impactful and dangerous gases causing climatic disasters around the globe. However, CO2 as the abundant C1 building block, through the conversion pathways
gives a plethora of opportunities to convert it into a wide range of commercial products and applications. The holistic approach among different conversion pathways is the electrochemical reduction of CO2 (eCO2R), ideally powered by renewable energy from intermittent sources such as wind and solar power. A silver bullet of the process is to find a catalyst that is active, selective, and stable. Copper has been recognized as the
only monometallic catalyst that can produce products that require a transfer of >2e-. However, in recent years the increased awareness of its reconstructive nature under eCO2RR-relevant conditions multiplied the complexity of the parameters that can
influence the reaction. Therefore overall thesis's approach to studying copper-based catalysts is based to understand the reconstructive aspect and the stability of Cu-based
catalysts, and deeply comprehend their relationship with the activity/selectivity. Chapter 1 gives an introduction to the recent activities in the field of carbon capture, utilization and storage (CCSU) technologies, the fundaments of CO2 as a molecule,
and its pathway toward state-of-the-art discoveries in the eCO2
R reaction. Afterward, the thesis focuses on the main experimental technique to produce nanostructured copper-based materials, namely, electrodeposition (Chapter 2). A big part of the thesis focuses on the establishment of an electrochemical setup for activity/selectivity measu
rement. The setup consists of two parts: 1) construction of the custom-made gas-tight sandwich-type electrochemical cell and 2) optimization of the online gas and ex-situ liquid product detection. After the establishment of the reliable electrochemical setup, Chapter 3 focuses on electrochemically
-grown Cu2O nanocubes catalyst and how the reconstructive nature induced by a particular electrochemical protocol influences on boost in activity/selectivity for methane production. The last part of the thesis consists contribution to the fundamental understanding of the degradation mechanisms and stability of Cu
-based catalysts under eCO2RR conditions. A unique ex-situ approach, mirrored in identical location scanning electron microscopy (IL-SEM) method is employed to study electrodeposited spherical half-micron particles on the glassy carbon rotating disk electrode (GC-RDE). With this evidence, we could interpret the observed structural changes as two separate electrochemical processes occurring one after another, namely copper dissolution from pre-oxidized native nanoparticles and subsequent (electro
-) redeposition of the dissolved copper species in a form of n
ew smaller Cu fragments.
Ključne besede: electrocatalysts, electrochemical CO2 reduction, copper nanoparticles, IL-SEM, stability, degradation
Objavljeno v RUNG: 14.11.2023; Ogledov: 3002; Prenosov: 29
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5. Silica-coated ▫$Bi2_Se_3$▫ topological insulator nanoparticles: preserving their optical properties and make them biocompatible : preserving 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, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: topological insulator, bismuth selenide, photo-thermal material, biocompatibility, nanoparticles
Objavljeno v RUNG: 19.10.2023; Ogledov: 2282; Prenosov: 4
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7. Separation of mercuric ions using 2-thienylbenzimidazole/cucurbit[7] uril/iron-oxide nanoparticles by pH controlFalguni Chandra, Paltan Laha, Farah Benyettou, Tina Škorjanc, Naʹil Saleh, 2023, izvirni znanstveni članek Opis: 2-Thienylbenzimidazole (TBI)/cucurbit[7]uril (CB7) host–guest complex was used as a motif to significantly improve the turnover of γ-Fe3O4 magnetic nanoparticles for potential application in the separation of toxic mercuric ions in polluted water samples. The mechanism of restoring the original solid materials is based on applying the pH-controlled preferential binding of the CB7 host to the TBI guest. The analytical application of this concept has not been realized in the literature. The pH-controlled stimuli-responsive abilities were confirmed in aqueous solution by the three-order of magnitudes higher stability constant of the protonated TBIH+/CB7 complex (e.g., K = 4.8 × 108 M−1) when compared to neutral TBI/CB7 complex (e.g., K = 2.4 × 105 M−1), also manifested in an increase in pKa values by ~ 3.3 units in the ground state. The supramolecular interaction and adsorption on iron oxide nanoparticles (NPs) were also spectroscopically confirmed in the solid state. The excited-state lifetime values of TBI/CB7NPs increased upon lowering the pH values (e.g., from 0.6 to 1.3 ns) with a concomitant blue shift of ~ 25 nm because of polarity effects. The time-resolved photoluminescent behaviors of the final solids in the presence of CB7 ensured pH-driven reusable systems for capturing toxic mercuric ions. The study offers a unique approach for the controllable separation of mercury ions using an external magnet and in response to pH through preferential binding of the host to guest molecules on the top of magnetic surfaces.
Ključne besede: iron oxide nanoparticles (IONPs), mercury, thienylbenzimidazole, cucurbit[n]uril
Objavljeno v RUNG: 13.07.2023; Ogledov: 3369; Prenosov: 7
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8. Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisationDarja Lisjak, Iztok Arčon, Matic Poberžnik, Gabriela Herrero‑Saboya, Ali Tufani, Andraž Mavrič, Matjaž Valant, Patricija Hribar Boštjančič, Alenka Mertelj, Darko Makovec, Layla Martin‑Samos, 2023, izvirni znanstveni članek Opis: Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
Ključne besede: barium hexaferrite, Fe XANES, EXAFS, magnetic nanoparticles
Objavljeno v RUNG: 06.07.2023; Ogledov: 3476; Prenosov: 8
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10. 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: 3765; Prenosov: 6
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