1990 Fiscal Year Final Research Report Summary
Basic Study on Design of Complex Oxide Catalysts of Two Components
| Project/Area Number |
01550754
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
反応工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAGAMOTO Hidetoshi Faculty of Engin., The Univ. of Tokyo, Res. Inst. Eng., Assoc. Prof., 工学部・総合試験所, 助教授 (40111471)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Complex Oxide / Catalyst / Perovskite Structure / Oxidation / XPS / TPD / XRD / Alkaline-earth Metal |
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| Research Abstract |
The aim of this research was to obtain criteria for design of complex oxide catalysts. We employed perovskite-type oxide as a complex oxide, and oxidation of methane as a test reaction. Obtained results are followings :
1. Relation between the preparation method of complex oxides and their catalytic activity was discussed for SrCeO_3. The basic sites are the active ones for methane oxidation over Ce-based perovskite-type oxides. The number of the basic sites increases with the temperature of the solid-state reaction of oxides.
2. Substitution of Li for A-site metal ion of BaCeO_3 and LaCeO_3 caused an increase of activity of oxidation. For LaCeO_3, activity increased with the ratio of Li substitution, which suggested that Oxygen vacancies formed by Li substitution play an important role. The activity change of C_2 formation paralleled that of CO_2 formation.
3. perovskite-type oxides containing Ce were very active. In the oxides, a part of Ce contained was reduced to trivalence, and there were a plenty of carbonate of Sr on the surface. It was suggested high activity of the oxides are due to O^- ions and/or oxygen vacancies. Oxygen desorbed at 300-500 ^ﾟC, which stems from the lattice oxygen, also plays an important role in methane oxidation.
4. The catalytic activities did not show a clear relationship with the change of bonding length between an oxygen ion and a metal ion.
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