In the search for the origin of the enhanced photocatalytic activity of composite TiO2-carbon systems, we have fabricated and analyzed well-defined model samples consisting of anatase and graphitic carbon with and without modifying the interface between them by a thin SiO2 space layer. 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 is mainly assigned to charge carrier leakage (transfer) at the interface between TiO2 nanocrystallites and the carbon film. (C) 2011 Elsevier B.V. All rights reserved.