Water and CO adsorptions were studied over the stoichiometric and the oxygen-deficient Cu₂O(111) surfaces, using thermal desorption spectroscopy (TDS), ultraviolet photoelectron spectroscopy (UPS), and X-ray photoelectron spectroscopy (XPS). Water is the only desorbing species detected in TDS and the extent of dissociation is unaffected by the surface condition: ≃ 0.25 monolayers of water dissociate on Cu₂O(111) regardless of surface condition. The local defect environment around oxygen vacancies does not play a significant role in the activity of the Cu₂O(111) surface for the dissociation of water. CO is found to bind molecularly to the surface through the carbon atom and with a heat of adsorption of 22 kcal/mol, higher value than that of CO on Cu₂O(100) (16.7 kcal/mol). This suggests that the local geometry of adsorption sites may play an important role in the way CO binds to Cu₂O surfaces. Electronic changes upon CO adsorption and the higher heat of adsorption indicate an increased σ-donor character for CO, with some π-backbonding interactions. The local defect environment around oxygen vacancies does not appear to affect CO adsorption on Cu₂O(111) surfaces. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/45628 |
| Date | 10 November 2009 |
| Creators | Christiaen, Anne-Claire |
| Contributors | Chemical Engineering, Cox, David F., Marand, Eva, Oyama, Shigeo Ted |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | vi, 79 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 31594015, LD5655.V855_1994.C575.pdf |
Page generated in 0.0027 seconds