New insight into the structure of dispersed titania by combining normal-mode analysis with experiment

Normal-mode analysis has been combined with experiment to gain new insight into the vibrational structure of dispersed titania. For the calculations, double- and tri-grafted hydroxylated titania species have been adapted to a model silica support based on polyhedral oligomeric silsesquioxane (POSS). The choice of hydroxylated models was validated by IR detection of the OH stretching band of dispersed titania (0.7 Ti/nm2). UV resonance Raman experiments have identified three titania-related vibrational features within the spectral region 900–1100 cm−1 due to TiOSi interphase, TiOSi in-phase and out-of-phase stretching vibrations. This behaviour is fully consistent with the results obtained by the normal-mode analysis.