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

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.

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► Designed and fabricated model photocatalyst systems of TiO2 and graphitic carbon.
► Charge carrier dynamics obtained from photoluminescence (PL) measurements.
► The higher photocatalytic activity is primarily related to charge carrier leakage.