PhD Thesis Defence Presentations - Theodora Ramantani

Presentation Title (Τίτλος Παρουσίασης): LPG steam reforming over supported noble metal catalysts and perovskite oxides
Presentation Type (Τύπος Παρουσίασης): PhD Thesis Defence Presentations
Speakers Full Name (Ονοματεπώνυμο): Theodora Ramantani
Speakers Affiliation (Προέλευση Ομιλητή): University of Patras, Department of Chemical Engineering
Seminar Room (Αίθουσα): "A. C. Payatakes" Library
Event Date: Wed, Mar 01 2023, Time: 17:00 - 20:00
Abstract (Περίληψη)

Hydrogen (H2) is an attractive energy carrier, as it combines high energy content and zero emissions of gaseous pollutants. Hydrogen can be produced through steam reforming of various hydrocarbons such as natural gas, ethanol, liquefied petroleum gas (LPG) and various petroleum derivatives. Due to its well-established distribution network, even in areas where natural gas is not available, LPG has the potential to meet the growing demand for hydrogen, which cannot currently be met by renewable energy resources. LPG consists mainly of propane (C3H8) and butane (C4H10) in different proportions, depending on its source.

In the first part of this doctoral thesis, the steam reforming reaction of propane: butane mixtures on supported noble metal catalysts is studied. Rh, Ru, Ir, Pt, Pd, and Re were used as the metal phase and the metal oxides Al2O3, TiO2, and CeO2-ZrO2 as supports. The catalysts, with a nominal metal loading of 1 wt%, were synthesized by the wet impregnation method. The results showed that the catalytic behavior of the materials depends strongly on the nature of both the metallic phase and the support. The Ru and Rh catalysts are characterized by high propane conversions and high selectivities toward H2, which are comparable to those of the reference 10%Ni/Al2O3 catalyst. The best results were obtained for the Ru/CeO2-ZrO2 catalyst, which is characterized by high activity, high selectivity toward H2, and excellent stability with time-on-stream. The high efficiency of Ru to gasify carbon deposits under reaction conditions, combined with the favorable redox properties of the CeO2-ZrO2 support result in the suppression of carbon accumulation on the catalyst surface.

In the next part of the thesis, the propane steam reforming (PSR) reaction is investigated over catalysts derived from LaNiO3. More specifically, the partial substitution of La by Sr in the A-sites of the LaNiO3 perovskite and/or of Ni by Ru or Rh in the B-sites of LaNiO3 and La0.8Sr0.2NiO3 was studied. The perovskite materials were prepared with the combustion synthesis method. Exposure of the as-prepared samples to reaction conditions resulted in the in-situ development of new phases including metallic Ni and La2O2CO3, which participate actively in the PSR reaction. The LaNiO3 catalyst is more active compared to La0.8Sr0.2NiO3, however, its performance does not change appreciably following the partial substitution of Ru for Ni. In contrast, the incorporation of Ru, and especially Rh in the La0.8Sr0.2NiO3 structure results in the development of catalysts with significantly enhanced catalytic performance, which is improved by increasing the noble metal content. The best results were obtained for the La0.8Sr0.2Ni0.9Rh0.1O3 catalyst, which exhibits high activity and selectivity toward H2, as well as excellent long-term stability. This is attributed to the presence of well-dispersed Rh crystallites on the catalyst surface, that act synergistically with Ni0 species.

Finally, the reaction network of propane-butane steam reforming over Rh/Al2O3, Ru/Al2O3, and Ru/CeO2-ZrO2 catalysts is investigated. The reaction was studied employing transient experiments to gain information about the effects of the support and the metal on the reaction mechanism and on the nature and reactivity of the adsorbed intermediate species formed over the catalytic surface as well as the gas phase products. The results showed that propane and butane are dissociatively adsorbed on the metal surface leading to the formation of C3Hx, C2Hx, and CHx species. These species interact with the adsorbed water, alumina hydroxyls, or the lattice oxygen from CeO2-ZrO2, generating formates, acetates, or carbonates. These species are further decomposed releasing COx species and H2. The Al2O3-supported catalysts facilitate the formation of formate and acetate species, whereas, on the Ru/CeO2-ZrO2 catalyst, the formation of carbonate species prevails. The Rh/Al2O3 catalyst was found to be more active for the steam reforming reaction, however, C2H4 and CH4 were observed in the gas phase, in addition to the desired products CO, CO2, and H2.

Speakers Short CV (Σύντομο Βιογραφικό Ομιλητή)



Theodora Ramantani graduated from the Department of Chemical Engineering, University of Patras (ChemEngUP), Greece in 2015. She holds an MSc (2017) from ChemEngUP and she currently is a Ph.D. candidate in the Laboratory of Heterogeneous Catalysis. She has served as a teaching assistant in Organic Chemistry, Polymers Laboratory, and Chemical Engineering Process Laboratory II undergraduate courses in ChemEngUP, and co-advised more than eleven (11) diploma theses in ChemEngUP.


Participation in research projects


Program title: “Development and Demonstration of complete process for the production of electrical energy from fuel cells through intermediate production of H2 via LPG steam reforming” (project code: T1EDK-02442) Co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship, and Innovation, under the call RESEARCH–CREATE–INNOVATE, (Ph.D. candidate).

02.2020-05.2020, 09.2021-09.2022

Program title: “Development and Demonstration of a photocatalytic Process for removing Pathogens and Pharmaceuticals from wastewaters” (project code: 2De4P) Implemented under the Action “H.F.R.I.-1st call for Research Projects to support Post-Doctoral Researchers”) funded by H.F.R.I. Hellenic Foundation for Research and Innovation and General Secretariat for Research and Technology (GSRT), (Ph.D. candidate).


Journal Publications

  1. A. Kokka, T. Ramantani, A. Petala, P. Panagiotopoulou “Effect of the nature of the support, operating, and pretreatment conditions on the catalytic performance of supported Ni catalysts for the selective methanation of CO”, Catalysis Today, 355 (2020) 832-843.
  2. T. Ramantani, G. Bampos, A. Vavatsikos, G. Vatskalis, D.I. Kondarides “Propane Steam Reforming over Catalysts derived from Noble Metal (Ru, Rh)-substituted LaNiO3 and La0.8Sr0.2NiO3 Perovskite Precursors”, Nanomaterials, 11 (2021) 1931.
  3. G. Bampos, T. Ramantani, P. Panagiotopoulou, X.E.Verykios “Effect of Support on the Reactive Adsorption of CO from Low CO Concentration Streams on the Surface of Pd based Catalysts”, Industrial & Engineering Chemistry Research, 60 (2021) 18722-18738.
  4. A. Kokka, T. Ramantani, P. Panagiotopoulou “Effect of Operating Conditions on the Performance of Rh/TiO2 Catalyst for the Reaction of LPG Steam Reforming”, Catalysts, 11 (2021) 374.
  5. T. Kentri, A. Trimpalis, A. Misa, E. Kordouli, T. Ramantani, S. Boghosian “Rethinking the molecular structures of WVIOx sites dispersed on titania: distinct mono-oxo configurations at 430 °C and temperature-dependent transformations”, Dalton Transactions, 51 (2022) 7455-7475.
  6. T. Ramantani, V. Evangeliou, G. Kormentzas, D.I. Kondarides “Hydrogen Production by Steam Reforming of Propane and LPG over supported metal catalysts”, Applied Catalysis B: Environmental, 306 (2022) 121129.
  7. A. Kokka, T. Ramantani, IV. Yentekakis, P. Panagiotopoulou “Catalytic performance and in situ DRIFTs studied of propane and simulated LPG steam reforming reactions on Rh nanoparticles dispersed on composite MxOy-Al2O3 (M: Ti, Y, Zr, La, Ce, Nd, Gd) supports”, Applied Catalysis B: Environmental, 316 (2022) 121668.


Conference Publications

  1. Catalyst’s preparation for methanol synthesis from CO2 hydrogenation, 14th Panhellenic Symposium of Catalysis, 2016, Patras (poster presentation).
  2. Methanol production by CO2 hydrogenation over CuO/ZnO/MxOy catalysts, 5th Panhellenic Conference Green Chemistry and Sustainable Development, 2017, Patras (oral presentation).
  3. Methanol production by hydrogenation of carbon dioxide over mixed oxides catalysts, 11th Panhellenic Scientific Conference on Chemical Engineering, 2017, Thessaloniki (poster presentation).
  4. CO2 hydrogenation over supported Pd catalysts, 15th Panhellenic Symposium of Catalysis, 2018, Ioannina (oral presentation).
  5. Catalytic performance of Cu/ZnO/MxOy catalysts (M=Al, Zr, Ga) for the CO2 hydrogenation, 15th Panhellenic Symposium of Catalysis, 2018, Ioannina (awarded poster presentation).
  6. Hydrogenation of carbon dioxide over supported Pd catalysts, 4th Workshop of Graduates and Postdocs in Chemical Engineering Sciences, 31 Οκτωβρίου 2018, Πάτρα, Ελλάδα (poster presentation).
  7. Steam reforming of propane over supported metal catalysts,12th Panhellenic Scientific Conference on Chemical Engineering, 29-31 May 2019, Athens (poster presentation).
  8. Propane steam reforming over supported noble metal catalysts, 5th Workshop of Graduates and Postdocs in Chemical Engineering Sciences, 6 November 2019, Patras (awarded poster presentation).
  9. Hydrogen production by steam reforming of propane over supported noble metal catalysts, 11th International Conference on Environmental Catalysis, 7-9 September 2020, Manchester (poster presentation).
  10. Study of propane steam reforming over Ni-based perovskite oxides, 1st Online Young Scientists Symposium on "Mineral Resources-Environment-Chemical Engineering, 26-28 February 2021 (oral presentation).
  11. Noble metal-substituted La0.8Sr0.2NixM1-xO3 (M: Ru, Rh) perovskite catalysts for propane steam reforming, World Sustainable Energy Days 2022, 5-8 April 2022, Wels (poster presentation).
  12. Steam reforming of LPG for hydrogen production over supported Rh and Ru catalysts, 13th Panhellenic Scientific Conference on Chemical Engineering, 2-4 June 2022, Patras (oral presentation).
  13. LaSrNiXO3 (X: Zn, Mg, Fe, Co, Al, Cu, Ga) as heterogeneous persulfate activators for Losartan degradation in aqueous media, 11th European Conference on Pesticides and Related Organic Micropollutants in the Environment & 17th Symposium on Chemistry and Fate of Modern Pesticides, 23-26 June 2022, Ioannina, (poster presentation).
  14. Steam reforming of LPG over Ni-based perovskite oxide catalysts, 16th Panhellenic Symposium of Catalysis, 20-22 October 2022, Chania (poster presentation).


Internship at the Chemical State Laboratory of Patras with title: Chemical testing of spirit drinks, wines, oils, and water.

Diploma Thesis in the Laboratory of Heterogeneous Catalysis entitled: Catalytic activation of CO2 for methanol synthesis.

MSc Thesis in the Laboratory of Heterogeneous Catalysis entitled: Catalytic hydrogenation of carbon dioxide to value-added products.


Languages: English, German