TY - JOUR
T1 - Carrier dynamics in TiO2 and Pt/TiO2 powders observed by femtosecond time-resolved near-infrared spectroscopy at a spectral region of 0.9-1.5 μm with the direct absorption method
AU - Iwata, Koichi
AU - Takaya, Tomohisa
AU - Hamaguchi, Hiro O.
AU - Yamakata, Akira
AU - Ishibashi, Taka Aki
AU - Onishi, Hiroshi
AU - Kuroda, Haruo
PY - 2004/12/30
Y1 - 2004/12/30
N2 - Femtosecond time-resolved near-infrared spectra of TiO2 and Pt/TiO2 powders are measured at the wavelength region of 0.9-1.5 μm with the direct absorption method. Broad absorption bands of charge carriers, mainly free and trapped electrons, are observed for TiO2 and Pt/TiO2. The absorption band shape changes with a time constant of 160 fs after the photoirradiation, which most probably reflects the trapping of the generated free electrons. Population decay curves of the carriers after 1 ps, obtained for three different pump light powers, are well-explained by the second-order decay kinetics with a common second-order rate constant, indicating nongeminate recombination of the electron-hole pairs. When Pt is loaded to TiO2, an additional decaying process of 2.3 ps is observed. This decay component represents the transfer of generated electrons from TiO 2 to Pt, which is consistent with the known increase of overall catalytic activities by the Pt cocatalyst.
AB - Femtosecond time-resolved near-infrared spectra of TiO2 and Pt/TiO2 powders are measured at the wavelength region of 0.9-1.5 μm with the direct absorption method. Broad absorption bands of charge carriers, mainly free and trapped electrons, are observed for TiO2 and Pt/TiO2. The absorption band shape changes with a time constant of 160 fs after the photoirradiation, which most probably reflects the trapping of the generated free electrons. Population decay curves of the carriers after 1 ps, obtained for three different pump light powers, are well-explained by the second-order decay kinetics with a common second-order rate constant, indicating nongeminate recombination of the electron-hole pairs. When Pt is loaded to TiO2, an additional decaying process of 2.3 ps is observed. This decay component represents the transfer of generated electrons from TiO 2 to Pt, which is consistent with the known increase of overall catalytic activities by the Pt cocatalyst.
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U2 - 10.1021/jp047531k
DO - 10.1021/jp047531k
M3 - Article
AN - SCOPUS:11344270550
SN - 1520-6106
VL - 108
SP - 20233
EP - 20239
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 52
ER -