Selective catalytic ammonia oxidation to nitrogen by atomic oxygen species on Ag (111)

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dc.citation.epage22994en_US
dc.citation.issueNumber41en_US
dc.citation.spage22985en_US
dc.citation.volumeNumber121en_US
dc.contributor.authorKaratok, M.en_US
dc.contributor.authorVovk, E. I.en_US
dc.contributor.authorKoc, A. V.en_US
dc.contributor.authorOzensoy, E.en_US
dc.date.accessioned2018-04-12T11:08:58Z
dc.date.available2018-04-12T11:08:58Z
dc.date.issued2017en_US
dc.departmentInstitute of Materials Science and Nanotechnology (UNAM)en_US
dc.departmentDepartment of Chemistryen_US
dc.description.abstractAmmonia-selective catalytic oxidation was studied on the planar Ag(111) single-crystal model catalyst surface under ultra-high-vacuum (UHV) conditions. A variety of oxygen species were prepared via ozone decomposition on pristine Ag(111). Surface coverages of oxygen species were quantified by temperature-programmed desorption (TPD) and X-ray photoemission spectroscopy techniques. Exposure of ozone on Ag(111) at 140 K led to a surface atomic oxygen (Oa) overlayer. Low-energy electron diffraction experiments revealed that annealing of this atomic oxygen-covered Ag(111) surface at 473 K in UHV resulted in the formation of ordered oxide surfaces (Oox) with p(5×1) or c(4×8) surface structures. Ammonia interactions with O/Ag(111) surfaces monitored by temperature-programmed reaction spectroscopy indicated that disordered surface atomic oxygen selectively catalyzed N-H bond cleavage, yielding mostly N2 along with minor amounts of NO and N2O. Higher coverage O/Ag(111) surfaces, whose structure was tentatively assigned to a bulklike amorphous silver oxide (Obulk), showed high selectivity toward N2O formation (rather than N2) due to its augmented oxygen density. In contrast, ordered surface oxide overlayers on Ag(111) (where the order was achieved by annealing the oxygen adlayer to 473 K) showed only very limited reactivity toward ammonia. The nature of the adsorbed NH3 species on a clean Ag(111) surface and its desorption characteristics were also investigated via infrared reflection absorption spectroscopy and TPD techniques. Current findings demonstrate that the Ag(111) surface can selectively oxidize NH3 to N2 under well-defined experimental conditions without generating significant quantities of environmentally toxic species such as NO2, NO, or N2O.en_US
dc.identifier.doi10.1021/acs.jpcc.7b08291en_US
dc.identifier.issn1932-7447
dc.identifier.urihttp://hdl.handle.net/11693/37294
dc.language.isoEnglishen_US
dc.publisherAmerican Chemical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1021/acs.jpcc.7b08291en_US
dc.source.titleJournal of Physical Chemistry Cen_US
dc.subjectAbsorption spectroscopyen_US
dc.subjectAmmoniaen_US
dc.subjectAtomsen_US
dc.subjectCatalytic oxidationen_US
dc.subjectCrystal atomic structureen_US
dc.subjectDesorptionen_US
dc.subjectElectronsen_US
dc.subjectOxidationen_US
dc.subjectOxygenen_US
dc.subjectOzoneen_US
dc.subjectPhotoelectron spectroscopyen_US
dc.subjectSilver compoundsen_US
dc.subjectSilver oxidesen_US
dc.subjectSingle crystalsen_US
dc.subjectTemperature programmed desorptionen_US
dc.subjectUltrahigh vacuumen_US
dc.subjectDesorption characteristicsen_US
dc.subjectDisordered surfacesen_US
dc.subjectExperimental conditionsen_US
dc.subjectInfrared reflection absorption spectroscopyen_US
dc.subjectOzone decompositionen_US
dc.subjectSelective catalytic oxidationen_US
dc.subjectTemperature-programmed reaction spectroscopiesen_US
dc.subjectX ray photoemission spectroscopyen_US
dc.subjectSilveren_US
dc.titleSelective catalytic ammonia oxidation to nitrogen by atomic oxygen species on Ag (111)en_US
dc.typeArticleen_US

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Institute of Materials Science and Nanotechnology (UNAM)
Department of Chemistry