2000 Fiscal Year Final Research Report Summary
Preparation, characterizations, and applications for heterometallic-oxides prepared by thermal decomposition of new heteronulear complexes
| Project/Area Number |
10650811
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
工業物理化学
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| Research Institution | Ehime University |
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Principal Investigator |
SADAOKA Yoshihiko Ehime univ, Faculty of engineering, Professor, 工学部, 教授 (50036422)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Heteronuclear complex / Thermal decomposition / Perovskite-type oxide / Fine particle / Gas sensor / NO_2 / Surface analysis |
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| Research Abstract |
Heterometalllic oxides are one of the promising material as electrodes of fuel cells and chemical sensors. We have been proposed the thermal decomposition of heteronuclear complexes as a new method for the preparation of di- or tri-metallic oxides. We found that heterometallic oxides with relatively high specific surface area were formed at low temperatures when heteronuclear hexacyano-complexes were used as precursors. The heteronuclear LaMn(dhbaen)(OH)(NO_3)(H_2O)_4 complex was synthesized and perovskite-type hexagonal LaMnO_3 was obtained by its thermal decomposition at 700 ℃. Particle size of the samples decomposed at 600 ℃ and 700 ℃ is ca. 20 nm and 50 nm, respectively. Furthermore, homogenious La_<1-x>Sm_xFeO_3, NdFe_<0.5>Co_<0.5>O_3, YBa_2Cu_3O_7 tri-metallic oxides were prepared using same method. LaFeO_3 and SmFeO_3 were applied for semiconductor-type NO_2 gas sensors and determined its surface structure using XPS.The number of adsorption sites for the sample prepared by this method was larger than that by solid reaction method. On the other hand, the change of the electrical conductivity for composite La_2CuO_4-CuO was strongly changed by the 10 ppm H_2S gas flow. The reaction of the composite oxide in H_2S gas was investigated to determine its mechanism.
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