A convincing explanation of why mixed phases of anatase and rutile TiO2 outperform individual polymorphs is lacking. An energetic band alignment of ~0.4 eV is now shown to exist between the two phases with anatase possessing the higher electron affinity. This observation explains the separation of photoexcited charge carriers between phases and could lead to improved photocatalysts.
- David O. Scanlon
- Charles W. Dunnill
- Alexey A. Sokol