Model Chromia Surface Chemistry: C2 Alkyl Fragment Reactions and Probe Molecule Interactions

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dc.contributor.authorBrooks, John Danielen
dc.contributor.committeechairCox, David F.en
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.committeememberHanson, Brian E.en
dc.contributor.committeememberMorris, John R.en
dc.contributor.committeememberOyama, Shigeo Teden
dc.contributor.departmentChemical Engineeringen
dc.date.accessioned2014-03-14T20:16:59Zen
dc.date.adate2010-10-29en
dc.date.available2014-03-14T20:16:59Zen
dc.date.issued2010-09-29en
dc.date.rdate2012-05-08en
dc.date.sdate2010-10-01en
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.en
dc.description.degreePh. D.en
dc.identifier.otheretd-10012010-210318en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10012010-210318/en
dc.identifier.urihttp://hdl.handle.net/10919/29161en
dc.publisherVirginia Techen
dc.relation.haspartBrooks_JD_D_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectethylen
dc.subjectethylideneen
dc.subjectethylidyneen
dc.subjectdehydrogenationen
dc.subjectWateren
dc.subjectchromiaen
dc.titleModel Chromia Surface Chemistry: C<sub>2</sub> Alkyl Fragment Reactions and Probe Molecule Interactionsen
dc.typeDissertationen
thesis.degree.disciplineChemical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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