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Kwak, Ja Hun
Molecular Catalysis lab
Research Interests
  • Heterogeneous catalysis, molecular catalysis, ASlumima, zeolites

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Effects of Sulfation Level on the Desulfation Behavior of Presulfated Pt-BaO/Al2O3 Lean NOx Trap Catalysts: A Combined H-2 Temperature-Programmed Reaction, in Situ Sulfur K-Edge X-ray Absorption Near-Edge Spectroscopy, X-ray Photoelectron Spectroscopy, and Time-Resolved X-ray Diffraction Study

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dc.contributor.author Kim, Do Heui ko
dc.contributor.author Szanyi, Janos ko
dc.contributor.author Kwak, Jahun ko
dc.contributor.author Wang, Xianqin ko
dc.contributor.author Hanson, Jonathan C. ko
dc.contributor.author Engelhard, Mark ko
dc.contributor.author Peden, Charles H. F. ko
dc.date.available 2015-07-23T02:12:12Z -
dc.date.created 2015-07-20 ko
dc.date.issued 2009-04 -
dc.identifier.citation JOURNAL OF PHYSICAL CHEMISTRY C, v.113, no.17, pp.7336 - 7341 ko
dc.identifier.issn 1932-7447 ko
dc.identifier.uri https://scholarworks.unist.ac.kr/handle/201301/12335 -
dc.identifier.uri http://pubs.acs.org/doi/abs/10.1021/jp900304h ko
dc.description.abstract Desulfation by hydrogen of presulfated Pt (2 wt %)-BaO(20 wt %)/Al2O3 with various sulfur loading (S/Ba = 0. 12, 0.3 1, and 0.62) were investigated by combining H-2 temperature programmed reaction (TPRX), X-ray photoelectron spectroscopy (XPS), in situ sulfur K-edge X-ray absorption near-edge spectroscopy (XANES), and synchrotron time-resolved X-ray diffraction (TRARD) techniques. We find that the amount of HS desorbed during the desulfation in the H-2 TPRX experiments is not proportional to the amount of initial sulfur loading. The results of both in situ sulfur K-edge XANES and TR-XRD show that at low sulfur loadings, sulfates were transformed to a BaS phase and remained in the catalyst rather than being removed as H2S. On the other hand, when the deposited sulfur level exceeded a certain threshold (at least S/Ba = 0.31) sulfates were reduced to form H2S, and the relative amount of the residual sulfide species in the catalyst was much less than at low sulfur loading. Unlike samples with high sulfur loading (e.g., S/Ba = 0.62), H2O did not promote the desulfation for the sample with S/Ba of 0.12, implying that the formed BaS species originating from the reduction of sulfates at low sulfur loading are more stable to hydrolysis. The results of this combined spectroscopy investigation provide clear evidence to show that sulfates at low sulfur loadings are less likely to be removed as H2S and have a greater tendency to be transformed to BaS on the material, leading to the conclusion that desulfation behavior of Pt-BaO/Al2O3 lean NOx trap catalysts is markedly dependent on the sulfation levels ko
dc.description.statementofresponsibility close -
dc.language ENG ko
dc.publisher AMER CHEMICAL SOC ko
dc.subject REDUCTION CATALYST ko
dc.subject STORAGE-REDUCTION ko
dc.subject REGENERATION ko
dc.subject XANES ko
dc.subject MECHANISM ko
dc.subject BAO/AL2O3 ko
dc.subject XAFS ko
dc.subject BAO ko
dc.title Effects of Sulfation Level on the Desulfation Behavior of Presulfated Pt-BaO/Al2O3 Lean NOx Trap Catalysts: A Combined H-2 Temperature-Programmed Reaction, in Situ Sulfur K-Edge X-ray Absorption Near-Edge Spectroscopy, X-ray Photoelectron Spectroscopy, and Time-Resolved X-ray Diffraction Study ko
dc.title.alternative Effects of Sulfation Level on the Desulfation Behavior of Presulfated Pt-BaO/Al2O3 Lean NOx Trap Catalysts: A Combined H-2 Temperature-Programmed Reaction, in Situ Sulfur K-Edge X-ray Absorption Near-Edge Spectroscopy, X-ray Photoelectron Spectroscopy, and Time-Resolved X-ray Diffraction Study ko
dc.type ARTICLE ko
dc.identifier.scopusid 2-s2.0-65549162341 ko
dc.identifier.wosid 000265529700065 ko
dc.type.rims ART ko
dc.description.wostc 13 *
dc.description.scopustc 13 *
dc.date.tcdate 2015-12-28 *
dc.date.scptcdate 2015-11-04 *
dc.identifier.doi 10.1021/jp900304h ko
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