作用スペクトル解析による懸濁系半導体光触媒の活性評価と制御

抄録

The analyses of the wavelength-dependent photocatalytic activity by taking action spectra are useful for the evaluation of an active crystalline phase of semiconductor photocatalysts that contain two or more polymorphic crystalline phases and/or the different chemical compositions of different photoabsorption characteristics. The action spectra of photocatalytic reactions of H₂ evolution, acetic acid decomposition, and Ag deposition were measured by using powdered titanium (IV) oxide (TiO₂) photocatalysts of anatase-rutile mixtures. The discrimination of anactive crystalline phase in powdered photocatalysts was performed by the comparison between the action spectra of photocatalytic reactions and the diffuse reflectance spectra of TiO₂ powders. The active phase was different depending on the kinds of photocatalytic reactions even if the same mixed TiO₂ powders were used as photocatalysts; the photocatalytic activity of H₂ evolution was not so different in the anatase and rutile phases included in the mixed TiO₂ powders, while anatase or rutile phases were more active for the acetic acid decomposition or Ag deposition reactions, respectively.