This thesis probes three technologically important metal-oxide systems; Pd nanoparticles supported on the TiO2(110) surface, acetate on TiO2(110) and Fe3O4(111). The orientation of CO adsorbed to a Pd/TiO2(110) model catalyst system was probed using X-ray photoemission electron microscopy (XPEEM) and near-edge X-ray absorption fine structure (NEXAFS). The absorbed CO molecules were found to have an off-normal polar orientation, relative to the basal plane of the substrate. The result was interpreted as an average of several sets of CO molecules absorbed and oriented orthogonally to various facets of the Pd nanoparticles, some of the facets themselves orientated with an angular separation from the basal plane. The acetate saturated TiO2(110) surface was examined using photoelectron spectroscopy (PES) and NEXAFS under UHV conditions as well as under increased pressures of acetic acid. The coverage and orientation of the adsorbed acetic acid were studied. It was found that a second 0.5 ML of acetate, additional to the half-monolayer film observed in UHV, develops under 0.01 Torr of acetic acid pressure. This second layer is thought to be hydrogen bonded to hydroxyl groups that are formed during the absorption of the first layer. Additionally, the 1st half-monolayer is shown to be slightly tilted, this is believed to be the effect of hydroxyls and to influence the tilt of the second layer. Structural characterisation work was carried out on the Fe3O4(111) single-crystal surface with low energy electron diffraction. Full characterisation was not possible due to incomplete experimental data, however, a novel version of the analysis software CLEED was developed to accommodate simultaneous mutliple domain analysis.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:632082 |
| Date | January 2014 |
| Creators | Mackenzie Dover, C. M. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1456184/ |
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