Mechanism of Singlet Oxygen Generation in Visible-Light-Induced Photocatalysis of Gold-Nanoparticle-Deposited Titanium Dioxide
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- 作者：Hironobu Saito ; Yoshio Nosaka
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：July 24, 2014
- 年：2014
- 卷：118
- 期：29
- 页码：15656-15663
- 全文大小：375K
- ISSN：1932-7455
文摘
Superoxide radical (O2鈥?/sup>) and singlet molecular oxygen (1O2) were successfully detected on gold-nanoparticle-deposited titanium dioxide (AuNP/TiO2) under visible-light irradiation for the first time. For the samples prepared with 13 commercially available TiO2 powders, the generations of O2鈥?/sup> and 1O2 in the AuNP/TiO2 aqueous suspensions were measured by chemiluminescence photometry and near-infrared emission, respectively. By investigating the effects of the particle size, the crystalline phase of TiO2, the solution pH, and the light intensity on the 1O2 generation, the following generation process was proposed. Under the plasmon resonance excitation, an electron in the AuNP transfers to the conduction band of TiO2 to reduce O2 to O2鈥?/sup> at the TiO2 surface. The produced O2鈥?/sup> is oxidized by the positive hole remained in the AuNP to generate 1O2. This mechanism could clearly explain the good correlation between the O2鈥?/sup> and 1O2 generations and the mixed crystalline phase effect of TiO2, which could not be explained by the other proposed mechanisms such as energy transfer and two-photon excitation.