Incorporation of TiO2 into mesoporous SiO2: from synthesis to photocatalytic applications

In this work, incorporation of aqueous titania sol into an ordered and disordered mesoporous silica materials is carried out by means of a sol-gel impregnation route, dedicating particular attention to the control of the Ti/Si molar ratio in order to tailor the composition of the resulting materials. The target systems are characterized by means of complementary analytical techniques, with the intention of gaining an insight into the interplay between their chemical-physical properties and processing conditions. The obtained nanomaterials are characterized by a porous morphology and a controllable dispersion of titania on the internal surface of SiO2-based systems. Concomitantly, surface chemical analyses highlight the formation of TiO2-SiO2 nanocomposites, with a progressive Ti depletion on the surface as the bulk titania content increased, suggesting the accommodation of TiO2 particles in the pore channels. The system photocatalytic activity was studied in two test reactions, namely the degradation of isopropanol and toluene in the gas phase. Relevant results are presented and critically discussed, with special focus on the interrelations between material properties and functional behavior.