On the mechanism of enhanced photocatalytic activity of composite TiO2/carbon nanofilms

We fabricated and analyzed well-defined model samples consisting of anatase and graphitic carbon films with and without modifying the interface between them by a thin SiO2 space layer. The study was performed in the search for the origin of the enhanced photocatalytic activity of composite TiO2--carbon systems observed previously by us, but also reported in number of publications. We found that the films with a TiO2/C interface show noticeably lower photoluminescence intensity and shorter carrier life times compared to single TiO2 films with the same thickness and composition. The stronger non-radiative recombination was mainly assigned to charge carrier leakage (transfer) at the interface between TiO2 nanocrystallites and the carbon film.