Appl, Cat. B, ,Volumes 111-112, 12 January 2012, Pages 636-640
Reaction mechanism of visible-light responsive Cu(II)-grafted Mo-doped SrTiO3 photocatalyst studied by means of ESR spectroscopy and chemiluminescence photometry.
Yoshio Nosaka, Shinichiro Takahashi, Yasufumi Mitani, Xiaoqing Qiu,(Univ. Tokyo) and Masahiro Miyauchi(Tokyo Inst Technol)
(Abstract)
The reaction mechanisms of visible-light responsive Cu(II)-grafted Mo-doped SrTiO3 (Cu(II)/MoSTO) photocatalyst and related photocatalysts were analyzed by means of ESR spectroscopy for detecting trapped carriers at 77K and chemiluminescence photometry for O2.- and H2O2 in aqueous suspension. On the irradiation of visible light, the reduction of grafted Cu2+ ions was observed by ESR measurements for both Cu(II)/MoSTO and Cu(II)/STO (Cu(II)-grafted undoped SrTiO3) photocatalysts. One electron reduction product for O2, i.e., O2.-, was detected in aqueous suspension by 442-nm irradiation for the Cu(II)-grafted samples. On the other hand, the amount of H2O2 detected as the two electron reduction product of O2 was a very small scale, indicating possible further reduction of H2O2 into H2O. From the ESR observations of crystalline defects, it was concluded that the Mo doping to increase visible-light response also increase the electron-hole recombination to some extent, while the Cu(II) grafting functioned as a trap of excited electrons to decrease the recombination.
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