1. Insight into the interdependence of Ni and Al in bifunctional Ni/ZSM-5 catalysts by Ni K-edge XAS analysisIztok Arčon, Hue-Tong Vu, Goran Dražić, Janez Volavšek, Gregor Mali, Nataša Zabukovec Logar, Nataša Novak Tušar, 2023, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Catalyst design is crucial for improving catalytic activity and product selectivity. In a bifunctional Ni/ZSM-5
zeolite type catalyst, catalytic properties are usually tuned via varying Al and Ni contents [1]. While changes in
acid properties associated with Al sites are usually closely investigated, Ni phases, however, receive inadequate
attention. Herein, we present a systematic structural study of Ni in the Ni/ZSM-5 materials by Ni K-edge
XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) analyses,
to monitor the local structure and chemical state of Ni species in the catalysts. In combination with XRD and
TEM we resolved the changes in the local environment of Ni species induced by the different Al contents of
the parent ZSM-5 prepared by a “green”, template free technique [2].
Ni species in Ni/ZSM-5 exist as NiO crystals (3–50 nm) and as charge compensating Ni2+ cations. The Ni Kedge
XANES and EXAFS results enabled the quantification of Ni-containing species. At a low Al to Si ratio
(nAl/nSi < 0.04), the NiO nanoparticles predominate in the samples and account for over 65% of Ni phases.
However, NiO is outnumbered by Ni2+ cations attached to the zeolite framework in ZSM-5 with a high Al to Si
ratio (nAl/nSi = 0.05) due to a higher number of framework negative charges imparted by Al. The obtained
results show that the number of highly reducible and active NiO crystals is strongly correlated with the
framework Al sites present in ZSM-5 zeolites, which depend greatly on the synthesis conditions. Therefore,
this kind of study is beneficial for any further investigation of the catalytic activities of Ni/ZSM-5 and other
metal-modified bifunctional catalysts.
Ključne besede: Ni/ZSM-5 catalysts, Ni EXAFS, XANES
Objavljeno v RUNG: 19.09.2023; Ogledov: 723; Prenosov: 3
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2. Periodic anti-phase boundaries and crystal superstructures in ▫$PtCu_3$▫ nanoparticles as fuel cell electrocatalystsAna Rebeka Kamšek, Anton Meden, Iztok Arčon, Primož Jovanovič, Martin Šala, Francisco Ruiz-Zepeda, Goran Dražić, Miran Gaberšček, Marjan Bele, Nejc Hodnik, 2023, izvirni znanstveni članek Objavljeno v RUNG: 19.09.2023; Ogledov: 748; Prenosov: 5
 Celotno besedilo (2,15 MB)
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3. Multicomponent Cu-Mn-Fe silica supported catalysts to stimulate photo-Fenton-like water treatment under sunlightAndraž Šuligoj, Ivalina Trendafilova, Ksenija Maver, Albin Pintar, Alenka Ristić, Goran Dražić, Wael H. M. Abdelraheem, Zvonko Jagličić, Iztok Arčon, Nataša Zabukovec Logar, Dionysios D. Dionysiou, Nataša Novak Tušar, izvirni znanstveni članek Ključne besede: Magnetic catalyst, Photocatalyst, Water treatment, Sunlight, Contaminants of emerging concern, Photo-Fenton-like systems, Cu, Mn, Fe, XANES, EXAFS
Objavljeno v RUNG: 06.07.2023; Ogledov: 1178; Prenosov: 5
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4. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: Iron oxide clusters, copper oxide clusters, alumina support, synergistic effect, low-temperature total catalytic oxidation, toluene, Cu, Fe XANES, EXAFS
Objavljeno v RUNG: 06.07.2023; Ogledov: 1022; Prenosov: 13
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7. Insight into the interdependence of Ni and Al in bifunctional Ni/ZSM-5 catalysts at the nanoscaleHue-Tong Vu, Iztok Arčon, Danilo Oliveira de Souza, Simone Pollastri, Goran Dražić, Janez Volavšek, Gregor Mali, Nataša Zabukovec Logar, Nataša Novak Tušar, 2022, izvirni znanstveni članek Opis: Catalyst design is crucial for improving catalytic activity and product selectivity. In a bifunctional Ni/ZSM-5
zeolite type catalyst, catalytic properties are usually tuned via varying Al and Ni contents. While changes in
acid properties associated with Al sites are usually closely investigated, Ni phases, however, receive
inadequate attention. Herein, we present a systematic structural study of Ni in the Ni/ZSM-5 materials by
using Ni K-edge XANES and EXAFS analyses, complemented by XRD and TEM, to resolve the changes in
the local environment of Ni species induced by the different Al contents of the parent ZSM-5 prepared
by a “green”, template free technique. Ni species in Ni/ZSM-5 exist as NiO crystals (3–50 nm) and as
charge compensating Ni2+ cations. The Ni K-edge XANES and EXAFS results enabled the quantification
of Ni-containing species. At a low Al to Si ratio (nAl/nSi # 0.04), the NiO nanoparticles predominate in
the samples and account for over 65% of Ni phases. However, NiO is outnumbered by Ni2+ cations
attached to the zeolite framework in ZSM-5 with a high Al to Si ratio (nAl/nSi ¼ 0.05) due to a higher
number of framework negative charges imparted by Al. The obtained results show that the number of
highly reducible and active NiO crystals is strongly correlated with the framework Al sites present in
ZSM-5 zeolites, which depend greatly on the synthesis conditions. Therefore, this kind of study is
beneficial for any further investigation of the catalytic activities of Ni/ZSM-5 and other metal-modified
bifunctional catalysts.
Ključne besede: Ni/ZSM-5 catalysts, zeolite, Ni XANES, EXAFS
Objavljeno v RUNG: 11.05.2022; Ogledov: 1563; Prenosov: 43
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8. Affinity-based isolation of extracellular vesicles by means of single-domain antibodies bound to macroporous methacrylate-based copolymerLidija Filipovic, Milica Spasojevic, Radivoje Prodanovic, Aleksandra Korac, Suzana Matijasevic, Goran Brajuskovic, Ario De Marco, Milica Popovic, 2022, izvirni znanstveni članek Ključne besede: nanobodies, immunopurification, extracellular vesicles, polymers
Objavljeno v RUNG: 18.03.2022; Ogledov: 1580; Prenosov: 0
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