1. Winning combination of Cu and Fe oxide clusters with an alumina support for low-temperature catalytic oxidation of volatile organic compoundsTadej Žumbar, Iztok Arčon, Petar Djinović, Giuliana Aquilanti, Gregor Žerjav, Albin Pintar, Alenka Ristić, Goran Dražić, Janez Volavšek, Gregor Mali, Margarita Popova, Nataša Zabukovec Logar, Nataša Novak Tušar, 2023, original scientific article Abstract: A γ-alumina support functionalized with transition metals is one of the most widely used industrial catalysts for the total oxidation of volatile organic compounds (VOCs) as air pollutants at higher temperatures (280−450 °C). By rational design of a
bimetal CuFe-γ-alumina catalyst, synthesized from a dawsonite alumina precursor, the activity in total oxidation of toluene as a model VOC at a lower temperature (200−380
°C) is achieved. A fundamental understanding of the catalyst and the reaction mechanism is elucidated by advanced microscopic and spectroscopic characterizations as well as by temperature-programmed surface techniques. The nature of the metal−support bonding and the optimal abundance between Cu−O−Al and Fe−O−Al species in the catalysts leads to synergistic catalytic activity promoted by small amounts of iron (Fe/Al = 0.005).
The change in the metal oxide−cluster alumina interface is related to the nature of the
surfaces to which the Cu atoms attach. In the most active catalyst, the CuO6 octahedra are
attached to 4 Al atoms, while in the less active catalyst, they are attached to only 3 Al atoms. The oxidation of toluene occurs via the Langmuir−Hinshelwood mechanism. The presented material introduces a prospective family of low-cost and scalable oxidation catalysts with superior efficiency at lower temperatures.
Keywords: Iron oxide clusters, copper oxide clusters, alumina support, synergistic effect, low-temperature total catalytic oxidation, toluene, Cu, Fe XANES, EXAFS
Published in RUNG: 06.07.2023; Views: 2722; Downloads: 27
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2. Removal of copper from aqueous solutions with zeolites and possible treatment of exhaust materialsNataša Zabukovec Logar, Iztok Arčon, Janez Kovač, Margarita Popova, 2021, original scientific article Abstract: The mechanism of Cu2+ loading into commercially available natural HEU-type and synthetic LTA-type zeolites for their
possible use in environmental processes, such as water and air treatment applications, was studied. Elemental analysis,
SEM/EDXS, XRD, XAS and XPS analyses revealed 4-fold coordination of Cu2+ cations with oxygen atoms in the pores, a
predominant location of copper atoms on the surface of crystallites and retained crystallinity of zeolites throughout the
processes. The post-treatment of Cu2+-loaded samples with HCl and/or NaCl solutions confirmed the predominantly
reversible sorption of copper on zeolites from aqueous solutions by ion-exchange mechanism and, therefore, excellent
regeneration possibilities for both types of zeolites. Furthermore, with the calcination of exhaust metal-loaded zeolites,
catalysts for total toluene oxidation reaction, as a model VOC pollutant, were obtained.
Keywords: Cu2+ ion exchange, Total toluene oxidation, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, Zeolite
Published in RUNG: 03.06.2021; Views: 2710; Downloads: 154
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3. Photocatalytic degradation of gaseous toluene by using TiO2 nanoparticles immobilized on fiberglass clothMinoo Tasbihi, Ioana Cǎlin, Andraž Šuligoj, Mattia Fanetti, Urška Lavrenčič Štangar, 2017, original scientific article Keywords: Titanium dioxide, immobilization, toluene, fiberglass cloth, gaseous photocatalysis
Published in RUNG: 25.01.2017; Views: 5669; Downloads: 0
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