| Project/Area Number |
17350079
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental chemistry
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| Research Institution | National Institute of Advanced Industrial Science and Technolog |
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Principal Investigator |
FUJITANI Tadahiro National Institute of Advanced Industrial Science and Technolog, Research Institute for Innovation in Sustainable Chemistry, Group Leader, 環境化学技術研究部門, 研究グループ長 (50190054)
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| Co-Investigator(Kenkyū-buntansha) |
HANEDA Masaaki National Institute of Advanced Industrial Science and Technolog, Research Institute for Innovation in Sustainable Chemistry, Senior Researcher, 環境化学技術研究部門, 主任研究員 (70344140)
KNAKAMURA Isao National Institute of Advanced Industrial Science and Technolog, Research Institute for Innovation in Sustainable Chemistry, Researcher, 環境化学技術研究部門, 研究員 (00357659)
TAKAHASHI Atsushi National Institute of Advanced Industrial Science and Technolog, Research Institute for Innovation in Sustainable Chemistry, Researcher, 環境化学技術研究部門, 研究員 (60357366)
MAEDA Yasushi National Institute of Advanced Industrial Science and Technolog, Research Institute for Innovation in Sustainable Chemistry, Researcher, 環境化学技術研究部門, 研究員 (30357983)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥15,000,000 (Direct Cost: ¥15,000,000)
Fiscal Year 2006: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2005: ¥10,000,000 (Direct Cost: ¥10,000,000)
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| Keywords | Nitrogen oxides / Direct decomposition / Oxidation / Catalytic active sites / Catalyst design / Iridium / Tungsten / Sulfur / バリウム / 窒素酸化物の分解 |
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| Research Abstract |
The decreased activity due to oxidation of the catalyst surface by oxygen contained in the feed is a serious problem in the direct decomposition of NO to N_2 and O_2 over solid catalysts. In this study, we investigated the NO decomposition properties using both model catalyst and real catalyst in order to clarify the structure of the effective surface for NO decomposition in the presence of O_2.
1.The NO decomposition proceeds on the Ir(111) surface, but no NO decomposition occurs on the Ir(111) surface exposed to O_2. In contrast, the Wdeposited Ir(111) surface exposed to O_2 showed the same NO decomposition activity as the Ir(111) surface, for which the formation of Ir-WOx species (x<3) was observed. We thus found that the surface composed from Ir and W is effective for NO decomposition in the presence of O_2. On the basis of the information obtained by model catalyst study, we examined the NO reactivity using the Ir-WO_3/SiO_2 powder catalyst. It was confirmed that the Ir-WO_3/SiO_2 catalyst has high NO dissociation ability and resistance to oxidation of Ir compared with the Ir/SiO_2 catalyst. Furthermore, we found that the addition of Ba to Ir-WO_3/SiO_2 significantly promoted NO decomposition activity, which was caused by the stabilization of metallic Ir due to the formation of complex oxides of Ba and W.
2.We found that the NO dissociation proceeds on the Ir surface in the presence of O_2 by coexisting SO_2, which was due to removal of adsorbed oxygen from the Ir surface by the reaction of oxygen with atomic sulfur produced from SO_2 dissociation. That is, the Ir surface was kept on metallic state in the presence of O_2 and SO_2. The effect of SO_2 on the preventing for the oxidation of the Ir surface was also observed for the Ir/SiO_2 powder catalyst.
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