Highly-dispersed iridium catalysts with sub-nanometer diameters for carbon monoxide oxidation

buir.advisorÖzensoy, Emrah
dc.contributor.authorHosseini, Seyedsaber
dc.date.accessioned2021-09-23T06:24:01Z
dc.date.available2021-09-23T06:24:01Z
dc.date.copyright2021-09
dc.date.issued2021-09
dc.date.submitted2021-09-21
dc.departmentDepartment of Chemistryen_US
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (Master's): Bilkent University, Department of Chemistry, İhsan Doğramacı Bilkent University, 2021.en_US
dc.descriptionIncludes bibliographical references. (leaves 82-89).en_US
dc.description.abstractNovel catalytic architectures composed of catalytic centers with sub-nanometer diameters for CO oxidation reaction were designed, synthesized, and characterized. Accordingly, well-dispersed iridium precious metal active sites were supported on various catalytic support materials. Namely, magnesium oxide (MgO), ceria (CeO2), lanthana-zirconia (La2O3–ZrO2) and titania-zirconia (TiO2–ZrO2) systems were chosen as different support systems. The favorable catalytic effect of highly-dispersed Ir active sites with sub-nanometer diameters were demonstrated in flow-mode catalytic performance tests, where the lower loadings of highly dispersed Ir sites showed comparable catalytic activity in CO oxidation to that of bigger Ir clusters with higher metal loading. Furthermore, influence of the catalyst pre-treatment conditions (e.g., reduction in H2, oxidation in O2, and calcination in air) on the catalyst structure and performance were also studied via XRD, Raman, BET, XPS, TEM, EDX, and in-situ FTIR spectroscopy techniques. Our results indicate that in all the catalytic systems, high-dispersion Ir sites can be generated on supports where Ir exists as small clusters with < 1 nm particle size. Moreover, catalyst pretreatment conditions revealed noticeable alterations in the catalyst structure in terms of average support particle size, reduction extent of the support, specific surface area, pore volume, pore size, and Ir oxidation state. Finally, catalytic performance results indicated that under reaction conditions yielding close to 100% CO conversion, 0.2 and 0.5 wt.% Ir catalysts led to comparable performance to that of 1 wt.% Ir catalyst demonstrating the advantage of catalytic systems with highly dispersed sub-nanometer diameter active sites with extremely low metal loading.en_US
dc.description.degreeM.S.en_US
dc.description.statementofresponsibilityby Seyedsaber Hosseinien_US
dc.format.extentxvi, 89 leaves : illustrations (color), charts (color) ; 30 cm.en_US
dc.identifier.itemidB133499
dc.identifier.urihttp://hdl.handle.net/11693/76540
dc.language.isoEnglishen_US
dc.publisherBilkent Universityen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectAir pollutionen_US
dc.subjectCO oxidationen_US
dc.subjectSub-nanometer diameteren_US
dc.subjectMetal-support systemen_US
dc.subjectHeterogeneous catalysisen_US
dc.subjectHigh dispersionen_US
dc.subjectSelectivityen_US
dc.subjectActivityen_US
dc.titleHighly-dispersed iridium catalysts with sub-nanometer diameters for carbon monoxide oxidationen_US
dc.title.alternativeKarbon monoksit oksidasyonu için yüksek yüzey dağılımlı ve nanometreden küçük çaplı iridyum katalizörleren_US
dc.typeThesisen_US
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