Dissertation
Molybdenum Carbide Particles Supported On Zeolites: Thermodynamics And Reaction Engineering On Nanoscale In Methane Steam Reforming
Washington State University
Doctor of Philosophy (PhD), Washington State University
2022
DOI:
https://doi.org/10.7273/000004994
Abstract
I reviewed current study on Ni – based catalysts used in the methane steam reforming (MSR) reaction and the roles of different type of promoters in the first two sections of Chapter 1. I noticed that most studies only focus on half of the big picture: coke formation. Particle sintering has mainly been considered and studied as a result of coking. Besides, the roles of promoters also often entangle with particle size and support effects. In the last section, I also reviewed the principle and application of calorimetry that has been employed in this dissertation.
In Chapter 2, I studied MSR reaction over Ni – FAU prepared by ion exchange and Ni - Mo2C/FAU in which Mo was introduced by impregnation. The results indicate that the deactivation of Ni - FAU is due to sintering and the addition of Mo2C inhibits Ni sintering process through promoting CH4 decomposition. Besides, excellent stability of Mo2C supported on zeolite Y was also observed and therefore in Chapter 3 and 4, employing high temperature oxides melt calorimetry, I systematically studied the thermodynamics of MoO3 and Mo2C supported on FAU with different Si/Al ratios. Our data show that 1) the interaction between Mo2C/MoO3 and FAU decreases with increasing Si/Al ratios; 2) the interaction between Mo2C and FAU is much stronger than that between MoO3 and FAU.
Another important factor determining catalysts’ performance is the interaction of reactants with active sites. With the assistance of direct gas adsorption calorimetry, I performed water adsorption on copper – mordenite (Chapter 5) and ruthenium supported on activated carbon (Chapter 6) which are one of the most promising catalysts for methane – to – methanol reaction and biomass hydrodeoxygenation reaction, respectively. Water is chosen as probe molecule because it’s either a reactant, a product, or impurity and plays important roles in the reaction processes.
Subsequently, I expand the thermodynamic study to energy storage materials such as transition metal layered double hydroxides (LDHs) (Chapter 7). By coupling multiple technologies, I elucidate that NiAl-LDHs become less stable as the Ni/Al ratio increases. Moreover, water–LDH interactions is important in stabilizing the excessive Ni sites on the surface.
Metrics
3 File views/ downloads
25 Record Views
Details
- Title
- Molybdenum Carbide Particles Supported On Zeolites
- Creators
- Xianghui Zhang
- Contributors
- Su S.H. Ha (Advisor)Di D.W. Wu (Advisor)Steven S.S. Saunders (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Voiland College of Engineering and Architecture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 268
- Identifiers
- 99901019841301842
- Language
- English
- Resource Type
- Dissertation