Elucidation of the electron energy structure of TiO 2 (B) and anatase photocatalysts through analysis of electron trap density.

A clear understanding of the electron energy structure of TiO 2 (B)/anatase is needed to study the related catalytic reactions and design new composite photocatalysts. In this study, the electron energy structures of TiO 2 (B) and anatase were estimated by analyzing the energy-resolved distribution of electron traps measured by reversed double-beam photoacoustic spectroscopy. In the mixture of TiO 2 (B) and anatase, interfacial charge-transfer excitation from anatase to electron traps of TiO 2 (B) was suggested. By analyzing this for TiO 2 (B), the electron level with a relatively high density of states was found to be located ∼0.07 eV deeper than that for anatase. Furthermore, a similar electron energy structure was suggested for a composite photocatalyst having a mixed phase of TiO 2 (B) and anatase.