Direct synthesis of Cerium(III)-incorporated SBA-15 mesoporous molecular sieves by two-step synthesis method

Cerium(III)-incorporated SBA-15 (Ce-SBA-15) mesoporous molecular sieves were successfully synthesized by a two-step direct synthesis method in acid media, and characterized by XRD, UV–vis, ESR, TEM, N2 adsorption and FT-IR. The Ce-SBA-15 samples prepared show highly ordered mesostructures with larger pore diameter, pore volume and uniform mesopore size distribution. The valence of cerium species incorporated into the frameworks of SBA-15 can be controlled by adjusting the pH value of the synthesis solution accurately. When the pH value of the solution is ⩽6.0, Ce(III)-SBA-15 can be synthesized. If the pH value is higher than 6.0, the cerium species exist in the SBA-15 sample in form of Ce(IV). Moreover, it can be found that the two-step synthesis method is a feasible, effective and simple method to expand the pore size and the pore volume of SBA-15.