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2. Utilizing structurally disordered AlMg-oxide phase in Cu/ZnO catalyst for efficient ▫$CO_2$▫ hydrogenation to methanolAndraž Mavrič, Gregor Žerjav, Blaž Belec, Matevž Roškarič, Matjaž Finšgar, Albin Pintar, Matjaž Valant, 2023, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: carbon dioxide, methanol, catalysis
Objavljeno v RUNG: 15.09.2023; Ogledov: 811; Prenosov: 4
 Celotno besedilo (99,69 KB)
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3. Structural disorder of AlMg-oxide phase supporting Cu/ZnO catalyst improves efficiency and selectivity for ▫$CO_2$▫ hydrogenation to methanolAndraž Mavrič, Gregor Žerjav, Blaž Belec, Matevž Roškarič, Matjaž Finšgar, Albin Pintar, Matjaž Valant, 2023, izvirni znanstveni članek Opis: The performance of the Cu/ZnO catalyst system with the AlMg-oxide phase is studied for CO2 hydrogenation to methanol. The catalyst is prepared by thermal treatment of the hydrotalcite phase containing intimately mixed metal cations in the hydroxide form. CuO in the presence of ZnO and disordered AlMg-oxide phase gets easily reduced to Cu during the hydrogenation reaction. Its catalytic activity at relatively low Cu metal content (∼14 at.%) remains stable during 100 hours on stream at 260 °C with constant space-time yield for methanol (∼1.8 gMeOH gcat−1 h−1) and high methanol selectivity (>85 %) The improved performance is attributed to the neutralization of surface acidity, increased number of weak basic sites in the disordered phase, and lower tendency for coke formation.
Ključne besede: carbon dioxide hydrogenation, heterogenous catalysis, methanol, reducibility
Objavljeno v RUNG: 02.06.2023; Ogledov: 998; Prenosov: 14
Celotno besedilo (1,12 MB) |
4. Alternative Recovery and Valorization of Metals from Exhausted Catalytic Converters in a New Smart Polymetallic CatalystSebastiano Tieuli, Franco Baldi, Iztok Arčon, Katarina Vogel-Mikuš, Michele Gallo, Laura Sperni, Oreste Piccolo, Stefano Paganelli, 2019, izvirni znanstveni članek Opis: A new metals-polymeric composite, Metx-EPS (I), was prepared
to be used as catalyst in water or in two-phase aqueous
conditions. The metals source was an exhausted catalytic
converter that was grinded and treated with an acidic solution at room temperature. After filtration, the solution was concentrated, neutralized and added to a broth of Klebsiella oxytoca DSM 29614 to produce (I) where metals are embedded in a peculiar polysaccharide structure (EPS). The composite was easily recovered from the fermentation broth and purified. The process protocol was verified many times and was shown to be reproducible satisfactorily. The % recovery of metals, originally present in the converter, was good as determined by atomic
absorption. The morphology and the chemical state of main
metals in (I) were investigated by X-ray absorption spectroscopy
methods (XANES and EXAFS). No metallic alloy seems to
be evident. The catalytic activity and a possible synergic effect due to the presence of the different metals was valuated in the hydrogenation of some substrates, valuable precursors for theproduction of fine chemicals.
Ključne besede: Biogenerated polymetallic exopolysaccharide, biphasic catalysis, hydrogenation, metals-polymeric
composite, new catalyst from metallic wastes, EXAFS, XANES
Objavljeno v RUNG: 06.05.2019; Ogledov: 3197; Prenosov: 0
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5. Synthesis of a Cu/ZnO Nanocomposite by Electroless Plating for the Catalytic Conversion of CO2 to MethanolMaja Pori, Iztok Arčon, Damjan Lašič Jurković, Marjan Marinšek, Goran Dražić, Blaž Likozar, Zorica Crnjak Orel, 2019, izvirni znanstveni članek Opis: The process of methanol synthesis based on the hydrogenation of CO2
was investigated over binary Cu/ZnO catalyst materials,
prepared by applying a novel electroless plating fabrication method. The activity of the produced catalytic samples
was determined at temperature range between 200 and 300 °C and the feedstock conversion data were supplemented with
a detailed microstructure analysis using high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction
(XRD) and Cu and Zn K-edge, X-ray absorption near-edge structure (XANES) measurements and extended X-ray
absorption fine-structure (EXAFS) measurements. It was confirmed that the disorder in the Cu crystallites created unique
geometrical situations, which acted as the additional reactive centres for the adsorption of the reactant molecule species.
Copper and zinc structural synergy (spill-over) was also demonstrated as being crucial for the carbon dioxide’s activation.
EXAFS and XANES results provide strong evidence for surface alloying between copper and zinc and thus the present results
demonstrate new approach applicable for explaining metal–support interactions.
Ključne besede: EXAFS, CuZn alloy, Spillover mechanism, CO2 valorization, Electroless deposition method, Heterogeneous
catalysis
Objavljeno v RUNG: 12.04.2019; Ogledov: 3562; Prenosov: 0
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