Direct synthesis and catalytic activity of ordered large pore titanium-substituted spherical SBA-15 molecular sieves

Titanium substituted highly ordered SBA-15 spheres with a diameter about 5 mu m in a ternary P123-H2O-HCl-TEOS system were prepared by the hydrothermal method and the catalytic activity in the epoxidation of cyclohexene was studied. The synthesized materials were characterized by XRD, ICP-AES, FT-IR, BET and SEM, UV-Vis and N-2 adsorption/desorption isotherms. The results show that incorporation of titanium into the framework of SBA-15 makes the surface area, pore diameter and pore volume increase and the pore walls slimmer than pure SBA-15. When the titanium content is above a critical value, TiO2 anatase forms on the material surface. The Ti-SBA-15 materials showed good catalytic activity for the oxidation of cyclohexene. The catalytic activity increases with an increase of Ti content and decreases when anatase TiO2 clusters are formed.