Virginia Tech
Model Chromia Surface Chemistry: C<sub>2</sub> Alkyl Fragment Reactions and Probe Molecule Interactions
Abstract
dc:description.abstractThe thermally induced reaction of chlorinated ethanes on the nearly-stoichiometric α-Cr₂O₃ (102) surface results in the formation of gas phase hydrocarbons including ethylene, ethane, acetylene, 2-butene, 2-butyne and dihydrogen, and deposition of surface chlorine adatoms. No surface carbon or combustion products are observed in any reactions indicating that no thermally induced C-C bond cleavage occurs and surface lattice oxygen is not incorporated into surface intermediates. A combination of photoemission and Auger electron spectroscopies indicates the surface reactions of the chlorinated ethanes proceed via C-Cl bond cleavage to form surface chlorine adatoms and surface C₂-alkyl hydrocarbon fragments (i.e. ethyl, ethylidene and ethylidyne). Temperature programmed desorption studies indicate that both ethyl and ethylidene intermediates are selective towards ethylene. However, ethylidyne is more selective towards acetylene, but also produces ethylene in significant quantities. Chlorine adatom deposition leads to deactivation of surface Cr reaction centers by simple site blocking. The interaction of water with nearly-stoichiometric α-Cr₂O₃ (001) and (102) surfaces is structure sensitive. Water is sensitive to the difference in coordination number of Cr surface cations between the two surfaces, and on the α-Cr₂O₃ (001) surface, water has also demonstrated sensitivity to the degree of surface Cr cation reduction (and/or reduced coordination). These observations allowed for the development of a surface treatment recipe for the nearly-stoichiometric (001) surface.
Degree
thesis:*- Name thesis:degree_name
- Ph. D.
- Level thesis:degree_level
- doctoral
- Discipline thesis:degree_discipline
- Chemical Engineering
- Department dc:contributor.department
- Chemical Engineering
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2010
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Brooks, John Daniel
- Chair dc:contributor.committeechair
-
- Cox, David F.
- Committee members dc:contributor.committeemember
-
- Davis, Richey M.
- Hanson, Brian E.
- Morris, John R.
- Oyama, Shigeo Ted
Subjects
dc:subject × 6Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-10012010-210318
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/29161