Pt/CeOx/ZrOx/γ-Al2O3 ternary mixed oxide DeNOx catalyst: surface chemistry and NOx interactions

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buir.contributor.authorOk, Zehra Aybegüm
buir.contributor.authorÖzensoy, Emrah
dc.citation.epage12863en_US
dc.citation.issueNumber24en_US
dc.citation.spage12850en_US
dc.citation.volumeNumber122en_US
dc.contributor.authorAndonova, S.en_US
dc.contributor.authorOk, Zehra Aybegümen_US
dc.contributor.authorDrenchev, N.en_US
dc.contributor.authorÖzensoy, Emrahen_US
dc.contributor.authorHadjiivanov, K.en_US
dc.date.accessioned2019-02-21T16:02:15Zen_US
dc.date.available2019-02-21T16:02:15Zen_US
dc.date.issued2018en_US
dc.departmentDepartment of Chemistryen_US
dc.departmentNanotechnology Research Center (NANOTAM)en_US
dc.description.abstractSurface chemistry and the nature of the adsorbed NOx species on a Pt/CeO2-ZrO2/Al2O3 catalyst were investigated by IR spectroscopy, X-ray diffraction, H2-temperature programmed reduction, and NOx-temperature programmed desorption. Parallel studies were also carried out with benchmark samples such as CeO2/Al2O3, ZrO2/Al2O3, CeO2-ZrO2/Al2O3 and Pt-supported versions of these materials. All samples were studied in their reduced and nonreduced forms. The use of CO as a probe molecule revealed that during the synthesis of the mixed-metal oxide systems, deposited zirconia preferentially interacted with the alumina hydroxyls, while deposited ceria was preferentially located at the Lewis acid sites. Despite the limited extent of Zr4+ ions incorporated into the CeO2 lattice, the reduction of ceria was promoted and occurred at lower temperatures in the presence of zirconia. When deposited on ZrO2/Al2O3, platinum formed relatively big particles and existed in metallic state even in the nonreduced samples. The presence of ceria hindered platinum reduction during calcination and yielded a high platinum dispersion. Subsequent reduction with H2 led to the production of metallic Pt particles. Consequently, NO adsorption on nonreduced Pt-containing materials was negligible but was enhanced on the reduced samples because of Pt0-promoted NO disproportionation. The nature of the nitrogen-oxo species produced after NO and O2 coadsorption on different samples was similar. Despite the high thermal stability of the NOx adsorbed species on the ceria and zirconia adsorption sites, the NOx reduction in the presence of H2 was much more facile over Pt/CeO2-ZrO2/Al2O3. Thus, the main differences in the NOx reduction functionalities of the investigated materials could be related to the ability of the catalysts to activate hydrogen at relatively lower temperatures.en_US
dc.description.provenanceMade available in DSpace on 2019-02-21T16:02:15Z (GMT). No. of bitstreams: 1 Bilkent-research-paper.pdf: 222869 bytes, checksum: 842af2b9bd649e7f548593affdbafbb3 (MD5) Previous issue date: 2018en_US
dc.description.sponsorshipThe authors gratefully acknowledge the financial support by the Bulgarian National Science Fund (project no. DN 19/2). We also thank the Bulgarian Academy of Sciences (BAS) and Technical Research Council of Turkey (TUBITAK) (BAS project code: 32-33-41/25.11.2015 and TUBITAK project code: 215M170). E.O. also acknowledges the scientific collaboration with TARLA project founded by the Ministry of Development of Turkey (project code: DPT2006K-120470). Authors acknowledge SASOL GmbH for providing Puralox alumina support materials.en_US
dc.identifier.doi10.1021/acs.jpcc.8b03186en_US
dc.identifier.eissn1932-7455en_US
dc.identifier.issn1932-7447en_US
dc.identifier.urihttp://hdl.handle.net/11693/49983en_US
dc.language.isoEnglishen_US
dc.publisherAmerican Chemical Societyen_US
dc.relation.isversionofhttps://doi.org/10.1021/acs.jpcc.8b03186en_US
dc.relation.projectDPT2006K-120470 - Bulgarian Academy of Sciences, BAS - British Antarctic Survey, BAS - Bulgarian National Science Fund, BNSF: DN 19/2 - 32-33-41/25.11.2015 - 215M170 - Sasolen_US
dc.source.titleJournal of Physical Chemistry Cen_US
dc.titlePt/CeOx/ZrOx/γ-Al2O3 ternary mixed oxide DeNOx catalyst: surface chemistry and NOx interactionsen_US
dc.typeArticleen_US

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