Photoluminescence Characteristics of TiO₂ and Their Relationship to the Photoassisted Reaction of Water/Methanol Mixture

Abstract

This work investigated the photoluminescence characteristics of TiO 2 and discussed the relationship between the photoluminescence features of TiO 2 and the photoassisted reaction of water/methanol mixture. It is found that anatase TiO 2 displays a visible luminescence band centered at about 505 nm and rutile TiO 2 mainly shows a near-infrared luminescence band centered at about 835 nm, which are respectively ascribed to the oxygen vacancies in anatase TiO 2 and the intrinsic defects in rutile TiO 2 . The visible luminescence band is easily quenched by the Pt deposited on the surface of TiO 2, while the near-infrared luminescence band is hardly influenced by the deposited Pt. It is suggested that the excited electrons trapped in the oxygen vacancies of anatase are facilely transferred to Pt to contribute to the photoassisted reaction, but the electrons trapped in the intrinsic defects of rutile are not.