Synthesis and characterization of hierarchical titania-silica monolith

• The hierarchical titania-silica monoliths possessed bicontinuous macropores.
• The hierarchical titania-silica monoliths possessed ordered mesopores.
• The addition of fluoride benefits much more titanium atoms incorporate into the framework of silica.
• The hierarchical titania-silica monolith had higher activity and selectivity than Ti-SBA-15.

Titania-silica monoliths with bicontinuous macropores and ordered mesopores were successfully prepared by a double-template technique. The influence of reactants on pore structures and Ti content was studied in detail. The results demonstrated that acid concentration in starting compositions has a great effect on morphologies of the final samples. Besides, it is also found that the changing of water-soluble organic polymers amount and triblock copolymers amount could adjust the pore size of macropores and the order degree of mesopores respectively. Moreover, the addition of fluoride benefits much more titanium atoms incorporate into the framework of silica. Compared with Ti-SBA-15, the hierarchical titania-silica monolith showed better performance on catalytic reaction of large molecules such as epoxidation of cyclohexene to cyclohexene oxide with isopropyl benzene hydroperoxide.

The hierarchical titania-silica monoliths were successfully prepared by a double-template technique. The obtained materials possessed bicontinuous macropores and ordered mesopores. The epoxidation reaction of cyclohexene to cyclohexene oxide with isopropyl benzene hydroperoxide showed that hierarchical titania-silica monolith had higher activity and selectivity than Ti-SBA-15 due to better diffusion property and the enhanced accessibility of catalytically active sites to bulk reactant molecules.Figure optionsDownload high-quality image (235 K)Download as PowerPoint slide