2006 Fiscal Year Final Research Report Summary
Mechanisms and Applications of Photocatalytic Reactions in the Gas Phase
| Project/Area Number |
14050028
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TATSUMA Tetsu The University of Tokyo, Institute of Industrial Science, Associate Professor (90242247)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Nobuyuki The University of Tokyo, Institute of Industrial Science, Research Associate (70431822)
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| Project Period (FY) |
2001 – 2006
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| Keywords | Photocatalyst / Titanium Dioxde / Encrgy Storage / Remote Oxidation / Photocatalytic Lithography / Multicolor Photochromism / Metal Nanoparticle / Plasmon Photoelectrochemistry |
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| Research Abstract |
Major mechanisms of photocatalytic remote oxidation and photocatalytic lithography were revealed to be as follows: hydrogen peroxide generated on a photocatalyst diffuses in the gas phase, followed by photolysis to hydroxyl radicals, which are the active species. Photocatalytic lithography was applied to development of multichannel biosensor arrays.
Regarding electron exchange between a photocatalyst with redox-active solids and the application to energy storage photocatalysts, photo-induced electron transfer and proton transport from TiO_2 to WO_3 and MoO_3 were studied. Quantum efficiencies and capacities of the reductive energy storage and effects of adsorbed water on the energy storage were studied. It was found that electron transfer is possible from Ni(OH)_2 to holes in photo-excited TiO_2. A TiO_2-Ni(OH)_2 composite film works as an oxidative energy storage photocatalyst. It should be able to remove some harmful compounds such as formaldehyde even after dark. An Ir oxide and a Ru oxide exhibit higher oxidation abilities as oxidative energy storage materials.
Regarding plasmon photoelectrochemistry of metal nanoparticles-semiconductor systems, multicolor photochromism of Ag nanoparticles-TiO_2 systems was found. In the mechanistic study of the photochromism, it was found that photo-induced charge separation at the metal nanoparticle-semiconductor interface plays an essential role. The charge separation process can be applied to solar cells and photocatalysis. I was evidenced that photoelectrochemical dissolution of Ag nanoparticles resonant with an incident light and deposition and growth of non-resonant Ag nanoparticles are responsible for the spectral changes.
Au nanostructures were developed and nanopyramids were found to exhibit a broad plasmon resonance band. Photoelectrochemical actuators, which swell and shrink in response to light were developed. Biosensors based on algal phototaxis were also developed.
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