Behavior of superoxide radicals formed on TiO2 powder photocatalysts studied by a chemiluminescent probe method

文献情報

出版日 2002-02-14

DOI 10.1039/B108441K

インパクトファクター 3.676

著者

Yoshio Nosaka, Masatsugu Nakamura, Tsutomu Hirakawa

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要旨

A luminol chemiluminescence (CL) probe method was successfully applied to the investigation of the superoxide radical (O2−˙) formed on photoirradiated TiO2 powders. For several kinds of commercially available TiO2 photocatalysts and their calcined samples, the amount of O2−˙ produced at the steady state was measured and found to increase with the secondary particle size or the degree of aggregation. The decay of O2−˙ for the non-calcined samples was as long as several hundred seconds and obeyed second order kinetics, indicating that disproportionation is the main deactivation pathway. For some TiO2 photocatalysts, oxidative species such as OH˙ radicals are suggested to exist for 1 s after irradiation. On the other hand, reductive photoinduced electrons may remain for several seconds after irradiation since the decay of O2−˙ starts after a delay of more than 1 s. On calcination at temperatures up to 1173 K, O2−˙ decays by a mechanism other than disproportionation, suggesting the prolonged lifetime of an oxidative species that can react with O2−˙.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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