| Project/Area Number |
09650902
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
TANAKA Tsunehiro Kyoto University, Engineering, Associate Professor, 工学研究科, 助教授 (70201621)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | carbon dioxide / photocatalyst / environmental catalyst / zirconium oxide / rhodium / titanium oxide / photoenergy / resction intermediate / 光還元 / 水素 / メタン / 逆水性ガスシフト反応 |
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| Research Abstract |
We found out that zirconium oxide is an effective catalyst which promotes the photoreduction of carbon dioxide with hydrogen gas as a result of searching for a photocatalyst available for fixation of carbon dioxide under an ambient condition. During the reaction, formate ions are formed as a surface intermediate from hydrogen and carbon dioxide and the formate intermediate reacts with carbon dioxide to form carbon monoxide and bicarbonate ion. The bicarbonate ion decomposes to hydroxyl and carbon dioxide being reduced to a formate ion. The reaction proceeds catalytically. On the other hand, photoreduction of carbon dioxide with methane also involves the formation of a formate intermediate. Methane is a hydrogen atom source for the reduction and resulting methyl or carbene deposit as a surface carbonaceous species. In the case where methane is used as a reductant, therefore, carbonaceous deposit covers the active site to lead to deactivation. Beside zirconium oxide, we found titania-supported rhodium can work as a catalyst for photoreduction of carbon dioxide converted into carbon monoxide and methane with hydrogen. The pretreatment of titania-supported rhodium can control the reaction selectivity. Methane is formed by the reduction of rhodium by normal hydrogenation and the reaction is enhanced by UV-irradiation. On the other hand, when the reaction is carried out over oxidized rhodium, carbon monoxide is produced selectively.
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