Characterization of oxide-based catalysts and model catalysts for renewable fuels
Author
Summary, in English
This thesis presents fundamental studies on oxide-based catalysts and model catalysts used for the synthesis of renewable fuels. The two investigated oxide catalysts are In2O3(111) model catalysts and NiMo-oxide catalysts.
The In2O3(111) surface is studied as a model system for In2O3-based catalysts used for CO2 hydrogenation to methanol. Specifically, the interaction of In2O3(111) with CO2, syngas and potential reaction intermediates were investigated using photoelectron spectroscopy and complementary DFT calculations. These investigations provide insights in the adsorption geometry of the respective molecules on the surface. Additionally, the poising effect of H2O and H2S on the CO2 adsorption on the In2O3(111) was investigated, showing how dissociated H2O limits the CO2 adsorption and how dissociated H2S blocks CO2 adsorption on the In2O3(111) surface.
The second part of this thesis investigates the reduction of NiMo-oxide catalysts on alumina support and compares it to the reduction behavior of different model systems for these catalysts. The in situ studies show that Ni and Mo facilitate each others reduction and highlight the impact of the alumina support and noble metal promotors on the reduction of the NiMo-oxide catalysts. To gain a detailed insight into the reduction process of NiMo-oxide catalysts, we designed a model system of these catalysts based on NiMoO4 nanoparticles and studied
their reduction, which proceeds through a phase separation of Ni- and Mo-oxide.
The In2O3(111) surface is studied as a model system for In2O3-based catalysts used for CO2 hydrogenation to methanol. Specifically, the interaction of In2O3(111) with CO2, syngas and potential reaction intermediates were investigated using photoelectron spectroscopy and complementary DFT calculations. These investigations provide insights in the adsorption geometry of the respective molecules on the surface. Additionally, the poising effect of H2O and H2S on the CO2 adsorption on the In2O3(111) was investigated, showing how dissociated H2O limits the CO2 adsorption and how dissociated H2S blocks CO2 adsorption on the In2O3(111) surface.
The second part of this thesis investigates the reduction of NiMo-oxide catalysts on alumina support and compares it to the reduction behavior of different model systems for these catalysts. The in situ studies show that Ni and Mo facilitate each others reduction and highlight the impact of the alumina support and noble metal promotors on the reduction of the NiMo-oxide catalysts. To gain a detailed insight into the reduction process of NiMo-oxide catalysts, we designed a model system of these catalysts based on NiMoO4 nanoparticles and studied
their reduction, which proceeds through a phase separation of Ni- and Mo-oxide.
Publishing year
2024-03-08
Language
English
Full text
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Document type
Dissertation
Publisher
Department of Physics, Lund University
Topic
- Chemical Process Engineering
Status
Published
Supervisor
- Johan Zetterberg
- Edvin Lundgren
- Hampus Nilsson
- Sara Blomberg
ISBN/ISSN/Other
- ISBN: 978-91-8039-988-3
- ISBN: 978-91-8039-988-0
Defence date
5 April 2024
Defence time
09:15
Defence place
Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund.
Opponent
- Zdenek Dohnalek (Prof.)