Izabela Czekaj

Cracow University of Technology

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Natalia Sobuś

Cracow University of Technology

Izabela Kurzydym

University of Warsaw

Oliver Kröcher

École Polytechnique Fédérale de Lausanne

Alexander Wokaun

Paul Scherrer Institute

J. Wambach

Paul Scherrer Institute

M. Witko

Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences

Núria López

Institut Català d'Investigació Química

John Mantzaras

Paul Scherrer Institute

Katarzyna A. Kacprzak

Paul Scherrer Institute

Javier Pérez‐Ramírez

ETH Zurich

Cooperative Institutions

Technical University of Denmark

Paul Scherrer Institute

ETH Zurich

Centre National de la Recherche Scientifique

École Polytechnique Fédérale de Lausanne

Uppsala University

Jagiellonian University

SLAC National Accelerator Laboratory

Cracow University of Technology

AGH University of Krakow

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DFT studies of oxidation routes for Pd9 clusters supported on γ-alumina

Physical Chemistry Chemical Physics (2012)

Katarzyna A. Kacprzak Izabela Czekaj John Mantzaras

This research is focused on the analysis of adsorbed bare and oxidized Pd(9) nanoparticles supported on γ-alumina. From first-principle density functional theory calculations, several configurations, charge transfer and electronic density of states have been analyzed in order to determine feasible paths for the oxidation process. Studies of Pd/PdO nanoparticles prove that they are stable at γ-alumina supports. It is shown that the Pd(9) nanoparticle favors dissociative adsorption of oxygen molecules. The most energetically preferable sites for adsorption are close to the contact between the cluster and the support, where one oxygen atom interacts with a 5-coordinated aluminium atom, and the remaining oxygen is in contact with the closest palladium atom. After first dissociation, one oxygen atom creates a bridge between the palladium atom and the 5-coordinated aluminium atom and the second oxygen atom moves to the top of the Pd(9) cluster, making a bridge between two palladium atoms. Subsequent dissociations arise analogously, with the difference that oxygen atoms in the second layer of the palladium cluster occupy hollow sides of the cluster. Investigation of the charge distribution in each oxidation step reveals that charge transfer increases towards the Pd/PdO nanoclusters. The electronic density of states indicates that gradual oxygen molecule adsorption and dissociation shift the highest states of the Pd/PdO nanoparticles in different ways. The overall investigation is found to be beneficial for studying methane oxidation.

Nanoclusters

Charge density

10.1039/c2cp40715a

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Citations (19)

Catalytic Transformation of Biomass-Derived Glucose by One-Pot Method into Levulinic Acid over Na-BEA Zeolite

Processes (2022)

Natalia Sobuś Izabela Czekaj

This article presents the results of the conversion of biomass-based glucose to levulinic acid (LA) with the use of Na-BEA commercial zeolite catalyst. For this purpose, synthetic zeolite BEA was used as a matrix. The glucose conversion process with the participation of Na-BEA zeolite allowed the following acids to be obtained: levulinic acid, lactic acid, pyruvic acid and formic acid. The highest yield of levulinic acid was achieved when processed for 1–5 h at 200–250 °C with 0.1 g and 0.6 g of Na-BEA catalyst. We also compare the one-pot heterogeneous process with similar homogeneous process using H2SO4 as catalyst.

Levulinic acid

10.3390/pr10020223

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Citations (5)

Role of support in industrial catalytic processes. Theoretical modeling Rola nośnika w przemysłowych procesach katalitycznych. Modelowanie teoretyczne

PRZEMYSŁ CHEMICZNY (2016)

Izabela Czekaj

10.15199/62.2016.10.11

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Conversion of dihydroxyacetone to carboxylic acids on pretreated clinoptilolite modified with iron, copper, and cobalt

Catalysis Communications (2022)

Natalia Sobuś Magdalena Król Marcin Piotrowski Barbara Michorczyk Izabela Czekaj

In this paper, we present the conditions for modifying the natural clinoptilolite zeolite and giving it catalytic properties by embedding in its structure active centers in the form of metals, such as iron, copper, and cobalt. Clinoptilolite as a catalyst matrix was subjected to ammonium exchange (Me-H-CLI) and hierarchization with hydrochloric acid (Me-da-CLI). Clinoptilolite was also used without modification of its structure (Me-0-CLI). The obtained zeolite catalysts were characterized by means of XRD, BET, DRS UV-VIS and FT-IR analyzes as well as Raman spectroscopy. Zeolite catalysts were used for the conversion of dihydroxyacetone (DHA) based biomass. The catalytic process was carried out by the one-pot method. On the basis of the analysis with the use of high-performance liquid chromatography (HPLC), the reaction products were determined together with their selectivity, yield and also conversion of raw material. During the conversion of DHA, the following organic acids were obtained: lactic acid (LAC), formic acid (FA), pyruvic acid (PAC), acetic acid (AD), and levulinic acid (LA). The highest lactic acid yield (66.2%) was achieved with Co-0-CLI, formic acid (93.6%) with Cu-H-CLI and 87.4% acetic acid with Fe-da-CLI.

Levulinic acid

Clinoptilolite

Dihydroxyacetone

10.1016/j.catcom.2022.106509

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Citations (20)

Catalytic Transformation of Biomass-Derived Hemicellulose Sugars by the One-Pot Method into Carboxylic Acids Using Heterogeneous Catalysts

Catalysts (2024)

Natalia Sobuś Marcin Piotrowski Izabela Czekaj

This article presents the conditions for the transformation of pulp containing mixtures that occur in the hemicellulose fraction derived from lignocellulosic biomass. Selected materials with strong acid centers were used as catalytic materials: ion exchange resins, including AMBERLYST 15(H) and DOWEX DR-G8(H), and selected zeolite in the hydrogen form of the Beta type (H-BEA). The group was marked with the abbreviations M1, M2 and M3, where it differs in the content of xylose, mannose, galactose, glucose, rhamnose and uronic acids. The catalytic process was carried out in the reactor as a one-pot technique at temperatures of 180–250 °C for 1–5 h. Based on the collected results, the transformation products of hemicellulose pulp were determined and the catalytic abilities of selected materials were determined. The proposed conditions led to the production of organic acids. Levulinic acid was obtained with a selectivity of 25.95% after 1 h of the process at a temperature of 250 °C with the participation of H-BEA, and lactic acid was obtained with a selectivity of 73.28% after 5 h of the process at a temperature of 250 °C using DOWEX DRG8(H). The presence of oxalic, propionic and acetic acids was also observed.

Hemicellulose

10.3390/catal14120857

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Citations (0)

Sulphur poisoning of Ni catalysts used in the SNG production from biomass: Computational studies

Catalysis Today (2010)

Izabela Czekaj Rudolf Paul Wilhelm Jozef Struis J. Wambach Serge M.A. Biollaz

Methanation

Catalyst poisoning

Particle (ecology)

10.1016/j.cattod.2010.10.078

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Citations (26)

Design of Co, Cu and Fe–BEA Zeolite Catalysts for Selective Conversion of Lactic Acid into Acrylic Acid

Catalysis Letters (2019)

Natalia Sobuś Barbara Michorczyk Marcin Piotrowski Łukasz Kuterasiński Damian K. Chlebda

Design of the catalytic properties and structure of zeolite materials play a key role in efficient transformation of biomass to sustainable chemicals. In the present study, we have designed theoretical and experimental approach for the production of acrylic acid (AA) from lactic acid (LA) over zeolite catalysts. Various BEA zeolites modified with metals (Co, Cu and Fe) were prepared using ion exchange and sonication methods. In the theoretical studies the metal M–O–M dimers have been found to be stable above oxygen bound with aluminium centers of BEA zeolite. The mechanism of direct LA dehydration over the Co–, Cu– and Fe–BEA zeolites has been proposed. Experimentally, the investigated catalysts trend in following byproduct formation: AA, propionic acid (PA), 2,3-pentanedione (2,3-PD) or acetaldehyde (AC). The best selectivity towards acrylic acid was achieved in the presence of the Co– and Cu–BEA catalysts prepared by the sonication method. Direct lactic acid dehydration into acrylic acid over Co–, Cu– and Fe–BEA zeolites.

Acrylic acid

Sonication

10.1007/s10562-019-02883-8

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Citations (15)

Sulphur poisoning of Ni catalysts in the SNG production from biomass: A TPO/XPS/XAS study

Applied Catalysis A General (2009)

Rudolf Paul Wilhelm Jozef Struis Tilman J. Schildhauer Izabela Czekaj M. Janousch Serge M.A. Biollaz

XANES

X-ray absorption spectroscopy

K-edge

Methanation

10.1016/j.apcata.2009.04.030

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Citations (114)

Nickel Deposition on ?-Al2O3: Modelling Metal Particle Behaviour at the Support

CHIMIA International Journal for Chemistry (2009)

Izabela Czekaj Francois Loviat J. Wambach Alexander Wokaun

Recently, surface modifications on a commercial Ni/Al2O3 catalyst during the production of methane from synthesis gas were investigated by quasi in situ X-ray photoelectron spectroscopy (XPS). The effect of the synthesis gas on the surface properties of the catalyst and on its activity under methanation conditions was studied on an atomic level. The conclusion was that the stability of Ni particles on the ?-Al2O3 support can be influencedby cluster growth phenomena, which influence both size and distribution of the metal particles. In this study, Ni deposition and cluster growth on model catalyst samples (10 nm thick, polycrystalline ?-Al2O3 on Si(100)) was investigated by XPS. The molecular structure of the catalyst was investigated using Density Functional Theory calculations (StoBe) with cluster model and non-local functional (RPBE) approach. Al15O40H35 clusterswere selected to represent the ?-Al2O3 (100) surface. Ni clusters of different size were cut from a Ni(100) surface and deposited on the Al15O40H35 cluster in order to validate the deposition model determined by XPS.

Methanation

Deposition

Particle (ecology)

10.2533/chimia.2009.193

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Citations (3)

Relaxation and electronic structure of the V2O3(0001) surface: ab initio cluster model studies

Surface Science (2003)

Izabela Czekaj K. Hermann M. Witko

Sesquioxide

Surface States

Surface layer

10.1016/s0039-6028(02)02547-5

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Citations (28)