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dc.contributor.advisorSholl, David S.
dc.contributor.authorLi, Liwei
dc.date.accessioned2015-06-08T18:15:05Z
dc.date.available2015-06-09T05:30:06Z
dc.date.created2014-05
dc.date.issued2014-04-07
dc.date.submittedMay 2014
dc.identifier.urihttp://hdl.handle.net/1853/53456
dc.description.abstractAs an important chemical raw material, alcohols can be used as fuels, solvents and chemical feedstocks to produce a variety of downstream products. With limited fossil fuel resources, alcohol synthesis from syngas reactions can be a potential alternative to the traditional petroleum based alcohol synthesis. Among many catalysts active for syngas to alcohol processes, alkali promoted Mo2C has shown promising performance. More interestingly, the alkali promoter was found to play an important role in shifting the reaction selectivity from hydrocarbons to alcohols. However, limited understanding of the mechanism of this alkali promoter effect is available due to the complexity of syngas reaction mechanism and low content of alkali added to the catalysts. In this thesis, we performed a comprehensive investigation of the alkali promoter effect with density functional theory (DFT) calculations as our primary tool. We first examine various Mo2C surfaces to determine a representative surface structure active to alkali adsorption. On this particular surface, we develop a syngas reaction network including relevant reaction mechanisms proposed in previous literature. With energetics derived from DFT calculations and a BEP relation, we predict the syngas reaction selectivity and find it to be in excellent agreement with experimental results. The dominant reaction mechanism and selectivity determining steps are determined from sensitivity analysis. We also propose a formation mechanism of alkali promoters on Mo2C catalysts that shows consistency between experimental IR and DFT computed vibrational frequencies. Finally, the effect of alkali promoters on the selectivity determining steps for syngas reactions are investigated from DFT calculations and charge analysis. We are able to rationalize the role of alkali promoters in shifting the reaction selectivity from hydrocarbons to alcohols on Mo2C catalysts.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technology
dc.subjectDensity functional theory
dc.subjectAlcohol synthesis
dc.subjectSyngas
dc.subjectCO hydrogenation
dc.subjectMolybdenum carbide
dc.subjectCatalyst
dc.subjectSurface
dc.subjectAlkali promoter
dc.titleDensity functional theory study of alcohol synthesis reactions on alkali-promoted Mo2C catalysts
dc.typeDissertation
dc.description.degreePh.D.
dc.contributor.departmentChemical and Biomolecular Engineering
dc.embargo.terms2015-05-01
thesis.degree.levelDoctoral
dc.contributor.committeeMemberBredas, Jean-Luc
dc.contributor.committeeMemberSievers, Carsten
dc.contributor.committeeMemberAgrawal, Pradeep K.
dc.contributor.committeeMemberJones, Christopher W.
dc.date.updated2015-06-08T18:15:06Z


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