| Co-Investigator(Kenkyū-buntansha) |
FUJISHIRO Yoshinobu Tohoku Uni., Inst.Chem.React.Sci., Research Associate, 反応化学研究所, 助手 (90271999)
UCHIDA Satoshi Tohoku Uni., Inst.Chem.React.Sci., Research Associate, 反応化学研究所, 助手 (60232849)
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| Research Abstract |
Layered compound/semiconductor nonocomposites incorporating semiconductor nanoparticles in the interlayer of layered compounds were fabricated and their photo-chemical properties were investigate. Semiconductors such as CdS, Fe_2O_3. CuO, NiO, MnO, TiO_2, etc. were successively intercalated in various layered compounds such as H_2Ti_4O_9, H_4Nb_6O_<17>, HCaNb_3O_<10>, HNbWO_6, HTaWO_6, etc. The thickness of semiconductor particles incorporated was less than 1 nm and the band gap energy was slightly larger than that of normal unsupported semiconductor crystals. Nonocomposites incorporating small band gap semiconductor such as CdS, Fe_2O_3, CuO, NiO and MnO showed efficient hydrogen evolution activity under visible light irradiation (wave length>400 am). On the other hand, nanocomposites incorporating TiO_2 and/or TiO_2 and Pt were capable to clevage water into hydrogen and oxygen without sacrificial hole acceptor by band gap irradiation. The excellent photocatalytic activity of semiconductor particles incorporated wad attributed to the charge separation by guest to host electron transfer. By analyzing the fluorescence life times of CdS and TiO_2 incorporated in H_2T_<14>O_9 and H4Nb_6O_<17>, it was confirmed that photoinduced electron in CdS and/or TiO_2 in the interlayer quickly transfer to the host layers. The electron transfer rate constant from CdS to H2Ti4O9 and/or H_4Nb_6O_<17> were determined as ca. 10^6 sec-1 and those from TiO_2 to H_2T_<14>O_9 and H_4Nb_6O_<17> were l08 sec^<-1>.
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