Improved silica-titania catalysts by chitin biotemplating

Silica-titania materials with improved catalytic performance were elaborated as mesoporous microparticles by combining sol-gel and spray-drying processes with the self-assembly properties of alpha-chitin nanorods acting as biotemplates. Three different synthesis approaches are discussed, leading to materials with varied textural and chemical characteristics studied by SEM, N-2 volumetry, TEM, XPS and DR-UV techniques. The use of water or ethanol as initial solvent for chitin nanorod suspensions, as well as the mixing conditions of the precursors, has been shown to have a significant impact on the final properties. Materials of specific surface areas of up to 590 m(2) g(-1) and porous volumes of up to 0.84 mL g(-1), with low surface Si/Ti ratio, could be disclosed. Properties were further investigated by employing the silica-titania materials as heterogeneous catalysts for the sulfoxidation of bulky model compounds. The location of Ti active sites at the pore surface has been maximized and allows for improved productivity.