The primary objective of this study was to characterise standard iron based Fischer- Tropsch catalysts by using the hydrogenation of CO at elevated temperatures and ambient pressure as a test reaction. The reaction test data is supplemented by the following analytical techniques; X-ray diffraction (XRD), Raman scattering, temperature programmed oxidation (TPO), transmission electron microscopy (TEM) and also inelastic neutron scattering (INS). The aim of these studies is to characterise the hydrocarbonaceous species present on the catalyst surface after reaction and to propose what role these hydrocarbonaceous species may play in the Fe/CO/H2 surface chemistry; be it active or not. These initial characterisation studies of the reacted iron catalysts were then extended to study the temporal dependence of these species with increasing reaction time. The application of inelastic neutron scattering is shown to provide a great deal of information regarding the hydrocarbonaceous component present in these types of systems. Therefore the application of INS and the subsequent result constitute the majority of the discussion of this study. The research objectives for this study can be listed as follows; 1. To prepare an iron oxide catalyst using a reproducible and controlled method and to characterise this material using the methods outlined previously. 2. To react the iron oxide catalysts using a representative test reaction for the purpose of characterising the surface species present after reaction. 3. To use inelastic neutron scattering to probe and gain a vibrational spectroscopic insight to the hydrocarbonaceous species present. 4. To study the temporal dependence of the hydrocarbonaceous species and how they alter with increasing time-on-stream. The thesis will begin with an introduction to Fischer-Tropsch catalysis, with a focus on iron-based Fischer-Tropsch catalysis. The discussion will move to some heightened analysis of some previously reported INS measurements of iron Fischer-Tropsch catalysts. This prelude will be followed by the main discussion of results, that is the characterisation of the reacted iron oxide catalyst using inelastic neutron scattering and the temporal study with increasing time-on-stream. The thesis will then finish with a discussion on a brief study investigating the role of promoters in iron based Fischer-Tropsch catalysts, which constitutes future work.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:646770 |
| Date | January 2015 |
| Creators | Warringham, Robbie |
| Publisher | University of Glasgow |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://theses.gla.ac.uk/6364/ |
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