Formation and behavior of singlet molecular oxygen in TiO2 photocatalysis studied by detection of near-infrared phosphorescence
Formation and behavior of singlet molecular oxygen in TiO2 photocatalysis studied by detection of near-infrared phosphorescence
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DOI：
10.1021/jp070028y
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发表时间：
2007-03-22
影响因子：
3.7
通讯作者：
Nosaka, Yoshio
中科院分区：
文献类型：
--
作者：
Daimon, Toshihiro;Nosaka, Yoshio
通过监测粉末型TiO 2光催化剂在1270 nm处的近红外磷光，在355 nm激光脉冲的照射下检测到单重态分子氧（O-1（2）），该单重态分子氧的产率很高。在不同的环境中，如在空气中和在H2O、D2 O和乙醇的悬浮液中，对在TiO 2（Degussa P25）上产生的O-1（2）的寿命测量表明，在没有反应物的情况下，猝灭主要发生在TiO 2表面。在空气中测量了10种商业TiO_2光催化剂产生O-1（2）的量子产率，其范围为0.12 ~ 0.38，而寿命范围为2.0 ~ 2.5 μ s。由于TiO 2表面的猝灭非常快，因此O-1（2）的形成和衰减过程与光生电子-空穴对的复合没有区别。量子产率的值表明，O-1（2）可能有助于一些有机分子在辐照的TiO 2表面的氧化。
Singlet molecular oxygen (O-1(2)), which was produced with a significant yield, was detected from a powder-type TiO2 photocatalyst irradiated with a 355-nm laser pulse by monitoring its near-infrared phosphorescence at 1270 nm. Lifetime measurements for the O-1(2) produced at TiO2 (Degussa P25) in various environments, such as in air and in suspensions of H2O, D2O, and ethanol, indicated that quenching takes place mainly at the TiO2 surface in the absence of reactants. Quantum yields for O-1(2) generation were measured for ten commercial TiO2 photocatalysts in air and ranged from 0.12 to 0.38, while the lifetimes ranged from 2.0 to 2.5 mu s. Since the quenching by the TiO2 surface is quite fast, the formation and decay processes of O-1(2) have not been distinguished from the recombination of the photogenerated electron-hole pairs. The values of quantum yield suggest that O-1(2) may contribute to the oxidation of some organic molecules at the irradiated TiO2 surface.