@article{KaluzaBehrensSchiefenhoeveletal.2011, author = {Kaluza, Stefan and Behrens, Malte and Schiefenh{\"o}vel, Nora and Kniep, Benjamin and Fischer, Richard and Schl{\"o}gl, Robert and Muhler, Martin}, title = {A Novel Synthesis Route for Cu/ZnO/Al2O3 Catalysts used in Methanol Synthesis: Combining Continuous Consecutive Precipitation with Continuous Aging of the Precipitate}, series = {ChemCatChem}, volume = {3}, journal = {ChemCatChem}, number = {1}, publisher = {Wiley}, issn = {1867-3899}, doi = {10.1002/cctc.201000329}, pages = {189 -- 199}, year = {2011}, language = {en} } @article{KaluzaMuhler2009, author = {Kaluza, Stefan and Muhler, Martin}, title = {On the precipitation mechanism and the role of the post-precipitation steps during the synthesis of binary ZnO-Al2O3 composites with high specific surface area}, series = {Journal of Materials Chemistry}, volume = {19}, journal = {Journal of Materials Chemistry}, number = {23}, publisher = {Royal Society of Chemistry (RSC)}, issn = {1364-5501}, doi = {10.1039/b902004g}, pages = {3914 -- 3922}, year = {2009}, language = {en} } @article{KaluzaMuhler2009, author = {Kaluza, Stefan and Muhler, Martin}, title = {On the Role of Aging, Washing, and Drying in the Synthesis of Polycrystalline Zinc Oxide by Precipitation: Combining Fast Continuous Mixing, Spray Drying and Freeze Drying to Unravel the Solid-State Transformations of the Precipitate}, series = {Catalysis Letters}, volume = {129}, journal = {Catalysis Letters}, number = {3-4}, publisher = {Springer}, doi = {10.1007/s10562-008-9818-5}, pages = {287 -- 292}, year = {2009}, language = {en} } @article{FailingKaluzaStrucks2023, author = {Failing, Luisa and Kaluza, Stefan and Strucks, Peter}, title = {Catalytic CO2 methanation: Providing optimal test conditions for kinetic investigations}, series = {Chemie Ingenieur Technik}, volume = {95}, journal = {Chemie Ingenieur Technik}, number = {5}, publisher = {Wiley}, issn = {1522-2640}, doi = {10.1002/cite.202200201}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-40026}, pages = {749 -- 753}, year = {2023}, abstract = {In the context of using renewable energies and recycling climate-changing gases, methanation of CO2 provides one possibility. However, volatile availability of renewable energies for hydrogen production and fluctuating CO2streams from different sources lead to enhanced demand in investigating the influence of dynamic process operation on the catalyst performance, including detailed kinetic characterization. Reliable kinetic measurements require isothermal temperature control and absence of macrokinetic diffusion limitations. Both were investigated in this work while the determination of steady-state kinetic parameters is part of ongoing studies. Furthermore, a detailed analysis with respect to the long-term-stability of the nickel-based catalyst was performed}, language = {en} } @article{WinterDiehlTelaaretal.2024, author = {Winter, Franziska Luise and Diehl, Patrick and Telaar, Pascal and Watermann, Clara Maria and Kaluza, Stefan and Muhler, Martin and Apfel, Ulf-Peter and Zeidler-Fandrich, Barbara}, title = {Influence of the catalyst precursor for cobalt on activated carbon applied in ammonia decomposition}, series = {Catalysis Today}, volume = {429}, journal = {Catalysis Today}, publisher = {Elsevier}, issn = {0920-5861}, doi = {10.1016/j.cattod.2023.114502}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46600}, pages = {9}, year = {2024}, abstract = {Ammonia is a key compound for storing and transporting green hydrogen. However, the efficient release of stored hydrogen through thermocatalytic ammonia decomposition is achievable only at temperatures around 600 °C, particularly with non-noble metal-based catalysts, which prove to be both ecologically and economically more feasible. In this study, electrically conductive activated carbon was selected as the catalyst support, chosen specifically for its suitability in achieving more energy-efficient direct reactor heating through the ohmic resistance of the catalysts. Cobalt salts were wet impregnated on activated carbon investigating the influence of different precursors (cobalt nitrate and cobalt acetate) and pyrolysis temperatures (400 °C and 600 °C) under N2 flow on the cobalt particle size and the incorporation of cobalt into the carbon matrix. TEM imaging and CO-chemisorption revealed well dispersed cobalt particles with sizes below 10 nm for the catalysts synthesized from the cobalt nitrate precursor. On the other hand, cobalt acetate led to about nine times larger Co agglomerates, which were partially detached from the carbon matrix. Moreover, this substantial difference in the Co particle size results in a significantly higher ammonia conversion for cobalt nitrate-based catalysts, achieving 94 \% of ammonia conversion at 600 °C. Furthermore, the long-term stability test of the cobalt nitrate-based catalyst resulted in a slight deactivation of only 2 \% ammonia conversion at 500 °C.}, subject = {Katalyse}, language = {en} } @inproceedings{WachtKaluzaFleiger2023, author = {Wacht, Anika and Kaluza, Stefan and Fleiger, Philipp}, title = {Carbon Capture and Utilization in Cement Industry—Aspects of the Production of E-Fuels by Upcycling Carbon Dioxide}, series = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, booktitle = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, editor = {Leipzig, Konrad von and Sacks, Natasha and Mc Clelland, Michelle}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031156014}, issn = {2194-0525}, doi = {10.1007/978-3-031-15602-1_44}, pages = {603 -- 612}, year = {2023}, subject = {Carbon dioxide capture and utilization}, language = {en} } @article{GreuelWatermannLohmannetal.2025, author = {Greuel, Marc and Watermann, Clara Maria and Lohmann, Heiko and Kaluza, Stefan and Apfel, Ulf-Peter and Zeidler-Fandrich, Barbara}, title = {The conversion of ethanol over 3d-metal saponite-like smectites}, series = {Materials Advances}, journal = {Materials Advances}, number = {6}, publisher = {Royal Society of Chemistry}, issn = {2633-5409}, doi = {10.1039/d4ma01036a}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-52973}, pages = {2885 -- 2898}, year = {2025}, abstract = {The replacement of fossil fuel processes with renewable pathways is critical to circumvent climate change and environmental risks. A process of interest is the production of 1,3-butadiene (BD), which is primarily derived as a by-product of naphtha steam cracking. A sustainable alternative path involves converting renewable ethanol to BD via the Lebedev process, which requires a catalyst with balanced redox, acidic, and basic sites. Due to the necessity of a multifunctional catalyst, existing materials for this reaction are either comprised of catalyst mixtures or supported catalysts. In this study, we introduce a bulk material, saponite, containing M-O-Si sites, which combine required catalytic sites for the ethanol to BD (ETB) reaction in one material. The product composition in ethanol conversion were strongly dependent on the type of 3d-metal used, while no conclusive correlation between surface properties, conversion, and product composition was observed. Herein, using V-Sap*, we achieved an ethene productivity of 448 gethene kgcat-1 h-1 (74\%) at 573.15 K. High acetaldehyde productivity was maintained with Cu-Sap* (466 gAcA kgcat-1 h-1, 49\%) at 573.15 K and Zn-Sap (528 gAcA kgcat-1 h-1, 55\%) at 723.15 K. Mg-Sap primarily produced ethene but also yielded 10 gBD kgcat-1 h-1 BD at 723.15 K. Higher BD outputs were observed with Ni-Sap (31 gBD kgcat-1 h-1 at 523.15 K) and Mn-Sap* (51 gBD kgcat-1 h-1 at 723.15 K). This underscores the potential of saponite-based materials for flexible product outputs in ethanol conversion, influenced by the choice of integrated 3d-metal.}, subject = {Butadien}, language = {en} } @techreport{FailingKaluzaStrucks2024, author = {Failing, Luisa and Kaluza, Stefan and Strucks, Peter}, title = {Power2Gas - Katalytische Methanisierung von CO₂ als Baustein einer erfolgreichen Energie- und Rohstoffwende}, address = {D{\"u}sseldorf}, organization = {Hochschule D{\"u}sseldorf}, issn = {2625-3690}, doi = {10.20385/opus4-4514}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-45143}, pages = {27}, year = {2024}, abstract = {Die katalytische Methanisierung von Kohlendioxid (CO2) mit Hilfe von elektrolytisch erzeugtem Wasserstoff (H2) aus erneuerbaren Energiequellen kann einen wichtigen Beitrag zur Reduktion von CO2-Emissionen leisten. Aufgrund einer immer st{\"a}rker fluktuierenden Energie- und Rohstoffbereitstellung spielt die M{\"o}glichkeit einer flexiblen, dynamischen Betriebsweise eine zunehmend große Rolle f{\"u}r zuk{\"u}nftige Technologien. Dies bedingt auch im Fall der katalytischen Methanisierung umfangreiche Untersuchungen, um zu ermitteln, inwieweit eine dynamische Fahrweise Auswirkungen auf Prozess und Katalysator besitzt. An diesem Punkt setzte das HiFF-Projekt Power2Gas an. So wurden verschiedene nickelbasierte Katalysatorsysteme synthetisiert, wobei sich der via Impr{\"a}gnierung hergestellte Ni/Al2O3-Katalysator sowohl aufgrund seiner guten Leistung als auch der praktikablen und reproduzierbaren Herstellung als geeignetes Benchmark-System f{\"u}r weitere Untersuchungen - vor allem im kinetischen Bereich - erwies. W{\"a}hrend umfassender Parametervariationen wurden kinetische Datens{\"a}tze im station{\"a}ren Zustand bestimmt, die zur Modellierung der katalysierten CO2-Methanisierung verwendet werden k{\"o}nnen. Dar{\"u}ber hinaus wurden in ausgew{\"a}hlten Versuchsreihen die isotherme Temperaturkontrolle und eine ausreichende Langzeitstabilit{\"a}t sichergestellt sowie makrokinetische Diffusionsbeschr{\"a}nkungen ausgeschlossen. Die Ergebnisse wurden in einer peer-review-Publikation ver{\"o}ffentlicht und auf zwei Konferenzen pr{\"a}sentiert. Sie waren zudem die Basis f{\"u}r eine erfolgreiche Masterarbeit und flossen in die Antragstellung im Rahmen des DFG-Programms „Großger{\"a}teaktion f{\"u}r Hochschulen f{\"u}r Angewandte Wissenschaften" ein.}, language = {de} } @book{MarziDeerbergDoetschetal.2017, author = {Marzi, Thomas and Deerberg, G{\"o}rge and D{\"o}tsch, Christian and Grev{\´e}, Anna and Hiebel, Markus and Kaluza, Stefan and Knappertsbusch, Volker and Maga, Daniel and M{\"u}ller, Torsten and Pflaum, Hartmut and Pohlig, Astrid and Renner, Manfred and Seifert, Ulrich and Stießel, Sebastian and Unger, Christoph and Wack, Thorsten and Weidner, Eckhard}, title = {Kohlendioxid, Biomasse und Regenerativer Strom - Ressourcen einer neuen Kohlenstoffwirtschaft?}, volume = {Umsicht-Diskurs}, number = {1}, publisher = {Fraunhofer-Institut f{\"u}r Umwelt-, Sicherheit- und Energietechnik}, address = {Oberhausen}, organization = {Fraunhofer-Institut f{\"u}r Umwelt-, Sicherheit- und Energietechnik}, isbn = {978-3-87468-358-6}, doi = {10.24406/UMSICHT-N-473349}, year = {2017}, language = {de} }