Utilization of reducible mixed metal oxides as promoters for the enhancement of sulfur regeneration in nsr catalysts

Simple item page
buir.advisorÖzensoy, Emrah
dc.contributor.authorSamast, Zehra Aybegüm
dc.date.accessioned2016-08-29T11:20:27Z
dc.date.available2016-08-29T11:20:27Z
dc.date.copyright2016-07
dc.date.issued2016-07
dc.date.submitted2016-08-18
dc.departmentDepartment of Chemistryen_US
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (M.S.): Bilkent University, Department of Chemistry, İhsan Doğramacı Bilkent University, 2016.en_US
dc.descriptionIncludes bibliographical references (leaves 92-98).en_US
dc.description.abstractPt functionalized binary, ternary, and quaternary oxides (e.g. Pt/BaO/CeO2/ZrO2/Al2O3) were synthesized by wetness impregnation method and characterized by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, in-situ Fourier Transform Infrared (FTIR), and temperature programmed desorption (TPD) techniques. Effect of the synthesis sequence on the NOx storage capacity was investigated by synthesizing subsequently impregnated and co-impregnated ternary oxides. Influence of BaO loading on NOx uptake of quaternary oxides was examined by utilizing two different BaO loadings namely; 8 wt% and 20 wt% on co-impregnated ternary oxide, Pt10-10CeZrAl. Co-presence of CeO2-ZrO2 oxide domains leads to an increase in NOx storage. As BaO loading increases in quaternary oxides, thermal stabilities of nitrates and nitrites increase due to the formation of bulk/ionic nitrates. Although BaO impregnation on co-impregnated ternary oxides leads to a decrease in specific surface area (SSA) values due to sintering, NOx adsorption on BaO-functionalized quaternary oxides was found to be higher than the BaO deficient ternary oxides. Upon sulfur poisoning, formation of strongly bound bulk/ionic sulfate/sulfite functional groups on BaO containing catalysts result in a need for higher temperatures for complete sulfur regeneration. Comparison of the CeO2-ZrO2 promoted systems with that of the Pt/ 20 wt% Ba/Al2O3 conventional NOx Storage Reduction (NSR) catalyst suggests that ceria-zirconia promotion enhances the sulfur tolerance. In conclusion, in this study a new NSR catalyst namely, Pt20Ba10-10CeZrAl, which is promoted with reducible mixed metal oxides, was synthesized and characterized. This novel NSR catalyst formulation revealed favorable sulfur resistance with minor sacrifice in NOx storage ability.en_US
dc.description.degreeM.S.en_US
dc.description.statementofresponsibilityby Zehra Aybegüm Samast.en_US
dc.embargo.release2017-01-01
dc.format.extentxix, 99 leaves : charts, graphics (some color).en_US
dc.identifier.itemidB153986
dc.identifier.urihttp://hdl.handle.net/11693/32181
dc.language.isoEnglishen_US
dc.publisherBilkent Universityen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectNSRen_US
dc.subjectDeNOxen_US
dc.subjectCatalysten_US
dc.subjectBaOen_US
dc.subjectPten_US
dc.subjectCeO2en_US
dc.subjectZr2Oen_US
dc.subjectAl2O3en_US
dc.subjectNOx storage capacityen_US
dc.subjectSulfur poisoningen_US
dc.titleUtilization of reducible mixed metal oxides as promoters for the enhancement of sulfur regeneration in nsr catalystsen_US
dc.title.alternativeİndirgenebilir karışık metal oksitlerin kullanımı ile ndi katalizörlerinin kükürt direncinin artırılmasıen_US
dc.typeThesisen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
ZehraAybegum Samast-MasterThesis-17.08.2016.pdf
Size:
3.67 MB
Format:
Adobe Portable Document Format
Description:
Full printable version
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Dept. of Chemistry - Master's degree