Catalytic hydrogenation of carbon dioxide via plug-flow dielectric barrier discharge (DBD) plasma reactors

Αστερίου, Ζωή; Asteriou, Zoi

dc.contributor.author	Αστερίου, Ζωή	el
dc.contributor.author	Asteriou, Zoi	en
dc.date.accessioned	2025-01-17T10:08:18Z
dc.date.available	2025-01-17T10:08:18Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/60854
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.28550
dc.rights	Default License
dc.subject	Catalytic hydrogenation of CO2 in plasma reactor	en
dc.title	Catalytic hydrogenation of carbon dioxide via plug-flow dielectric barrier discharge (DBD) plasma reactors	en
heal.type	bachelorThesis
heal.classification	Κατάλυση	el
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2024-07-11
heal.abstract	The current thesis focuses on the catalytic hydrogenation of carbon dioxide (CO2) using both thermal and plasma methods. The catalysts used for this thesis were: CeO2, CeO2/CuO 10%, and CeO2/CuO 20% and the main focus was to assess their efficiency, selectivity to valuable products and stability. The thesis begins by exploring the theoretical background of CO2 emissions and introducing the CO2 hydrogenation reaction and its possible pathways. After discussing the possible products that can be acquired by the reaction, then the non-noble catalysts that facilitated the reaction were analyzed. Particularly, cerium oxide (CeO2) and copperdoped cerium oxide (CeO2/CuO 10%, and CeO2/CuO 20%). The materials used in the experiments include CO2, hydrogen (H2), and helium (He) gases, along with the catalysts that have already been mentioned. The experiments were separated into two categories: thermal and plasma. For the thermal experiments, a conventional oven was used as a source of energy, while for the plasma experiments, a plug-flow dielectric barrier discharge (DBD) plasma reactor was used. For the thermal method, experiments were conducted in various temperatures, starting from 20 °C and reaching 500 °C, to determine the temperature at which each catalyst becomes active, and the reaction takes place. CeO2 was the weakest catalyst since it demonstrated minimal CO2 conversion at lower temperatures. The reactants started to convert at 500 °C. The introduction of CuO to CeO2 significantly enhanced catalytic performance. CeO2/CuO 20% achieves the highest CO2 conversion rates, at the lowest temperatures (300 °C). This improved catalytic behavior is because of the synergistic effect of CuO, which creates more active sites for CO2 adsorption and improves the reduction process. For the plasma experiments, the CO2 conversion was stable as a function of time. The variable that was examined was how the CO2 conversion was affected by the different applied voltages. Without a catalyst, CO2 conversion increased with voltage, reaching up to 16% at 10 kV. The addition of the catalysts significantly improved the conversion and stability of plasma. CeO2/CuO 20% showed once again the best catalytic performance achieving 26% conversion at 10 kV. The plasma method was proved to be a very efficient method since in room temperature, we were able to accomplish an adequate conversion. Catalytic hydrogenation of carbon dioxide via plug-flow dielectric barrier discharge (DBD) plasma reactor Asteriou Zoi, 07.2024 Page 5 of 79 A comparative analysis of the thermal and plasma methods revealed that plasma-assisted CO2 hydrogenation offers distinct advantages, particularly in terms of energy efficiency and catalytic activity at lower temperatures. The CeO2/CuO 20% catalyst appeared to have the best performance in both methods. The last part of the experiment was the stability tests on the CeO2/CuO 20% catalyst. Firstly, the catalyst was reduced with H2 at 500°C and then it was tested under plasma conditions at 10 kV. The results showed consistent CO2 conversion rates over extended periods. This shows that the catalyst can be used for long-term plasma-assisted CO2 hydrogenation processes. To sum up, this study highlights the importance of catalysts in CO2 utilization. Future research should focus on finding the optimal plasma parameters such as voltage, gas flow ratios as well as exploring new catalyst compositions. Future research could also investigate whether the additional loading of CuO results in even better conversions. Additionally, the long-term stability of the catalyst should be further examined in order to conclude whether such a process could be scaled up. Concluding, this thesis emphasizes how the catalytic hydrogenation of CO2under thermal and plasma sources, combined with non-noble catalysts can efficiently convert a pollutant to chemically valuable products.	en
heal.advisorName	Αργυρούσης, Χρήστος	el
heal.committeeMemberName	Καραντώνης, Αντώνης	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Χημικών Μηχανικών. Τομέας Σύνθεσης και Ανάπτυξης Βιομηχανικών Διαδικασιών (IV). Εργαστήριο Τεχνολογίας Ανόργανων Υλικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	79 σ.	el
heal.fullTextAvailability	false