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2004 Fiscal Year Final Research Report Summary

Improvement of catalyst for selective reduction of NO by controlling reaction atmospheres

Research Project

Project/Area Number 14350425
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 触媒・化学プロセス
Research InstitutionNagoya University

Principal Investigator

SATSUMA Atsushi  Nagoya University, Graduate School of Engineering, Professor, 工学研究科, 教授 (00215758)

Co-Investigator(Kenkyū-buntansha) YOSHIDA Hisao  Nagoya University, Eco Topia Science Institute, Associate Professor, エコトピア科学研究機構, 助教授 (80273267)
SHIMIZU Ken-ichi  Nagoya University, Graduate School of Engineering, Research Associate, 工学研究科, 助手 (60324000)
Project Period (FY) 2002 – 2004
KeywordsNOx / Selective Reduction / Catalyst / Reaction atmospheres / Reaction mechanism / in-situ spectroscopy / Dynamics of active species / Diesel engine
Research Abstract

The addition of hydrogen in the reaction atmosphere is effective in promoting the activity of Ag/alumina and Ag-zeolites on the selective reduction of NO by hydrocarbons (HC-SCR) at low temperatures. The increment of NO conversion over Ag-MFI corresponds to the periodic addition of hydrogen into C_3H_8-SCR conditions. The UV-Vis spectra of Ag-MFI have revealed that the addition of hydrogen results in the formation of Ag_n^<□+> clusters due to partial reduction and agglomeration of Ag species The coincidence of the formation of the Ag_n^<□+> clusters and the increment of NO conversion suggests that Ag_n^<□+> clusters are the highly active species for HC-SCR. From analysis by H_2-TPR, UV-Vis, and EXAFS, the structure of Ag_n^<□+> clusters on Ag-MFI is identified as being Ag_4^<2+> on average. The formation of Ag clusters was strongly affected by the type of zeolites : The major Ag species are Ag^+ ions for MOR, Ag_n^<□+> clusters for MFI and BEA, and relatively large metallic Ag_m particles for Y. The sequence of Ag agglomeration (MOR<MFI<BEA<Y) is in accordance with the strength of the acid sites of zeolites. It can be expected that the interaction between the positive charge of Ag_n^<□+> clusters and acid sites, i.e., the ion-exchange site of zeolites, stabilizes Ag_n^<□+> clusters. The type of Ag species under HC-SCR conditions depends on the concentration of gas-phase oxidants (NO,O_2) and reductants (H_2,HC), and also on the number and strength of the zeolite acid sites.

  • Research Products

    (7 results)

All 2004

All Journal Article (7 results)

  • [Journal Article] Ag Cluster as Active Species for SCR of NO by propane in the Presence of Hydrogen over Ag-MFI2004

    • Author(s)
      J.Shibata, Y.Takada, A.Shichi, S.Satokawa, A.Satsuma, T.Hattori
    • Journal Title

      Journal of Catalysis 222

      Pages: 368-376

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Drastic Enhancement of SCR of NO over Ir Catalyst through Formation of Metallic Iridium on Na-zeolite2004

    • Author(s)
      J.Shibata, H.Yoshida, A.Satsuma, T.Hattori
    • Journal Title

      Chemistry Letters 33

      Pages: 800-801

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Adsorption-controlled Diffusion in Catalytic Reduction of NO with Hydrocarbons over Zeolite Catalysts2004

    • Author(s)
      A.Shichi, A.Satsuma, T.Hattori
    • Journal Title

      Catalysis Today 93-95

      Pages: 777-781

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Structure of active Ag clusters in Ag-zeolites for SCR of NO by propane in the presence of hydrogen2004

    • Author(s)
      J.Shibata, K.Shimizu, Y.Takada, A.Shichi, S.Satokawa, A.Satsuma, T.Hattori
    • Journal Title

      Journal of Catalysis 227

      Pages: 367-374

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Influence of zeolite support on activity enhancement by addition of hydrogen for SCR of NO by propane over Ag-zeolites2004

    • Author(s)
      J.Shibata, Y.Takada, A.Shichi, S.Satokawa, A.Satsuma, T.Hattori
    • Journal Title

      Applied Catalysis B : Environmental 54

      Pages: 137-144

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Factors controlling activity and selectivity for SCR of NO by hydrogen over supported Pt catalysts2004

    • Author(s)
      J.Shibata, M.Hashimoto, K.Shimizu, H.Yoshida, T.Hattori, A.Satsuma
    • Journal Title

      Journal of Physical Chemistry, B 108

      Pages: 18327-18335

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Factors controlling activity and selectivity for SCR of NO by hydrogen over supported Pt catalysts2004

    • Author(s)
      J.Shibata, M.Hashimoto, K.Shimizu, H.Yoshida, T.Hattori, A.Satsuma
    • Journal Title

      Journal of Physical Chemistry B 108

      Pages: 18327-18335

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2006-07-11  

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