Synthesis and characterization of lanthanide-incorporated FSM-16 type mesoporous silica

Noble FSM-16 type mesoporous silicas incorporating lanthanides (Ln = La, Ce, Pr) have been successfully synthesized by a modified sheet folding process of kanemite–CTAB system. For comparison, Ln-loaded FSM-16 was prepared by a simple impregnation method. The local structure of Ln species and pore structure were investigated by XRD, diffuse reflectance UV absorption, XAFS and N2 adsorption measurement. The impregnation causes the deposition of Ln species on the pore walls and thus decreases the pore size and pore volume. By contrast, Ln-incorporated FSM-16 exhibited mesoporosity comparable to the pristine FSM-16. XAFS analysis indicated that Ln species showed tetrahedral coordination and the Ln–O atomic distance was smaller than that of bulk oxide such as La2O3, CeO2 and Pr2O3. The pore structure of Ln–FSM-16 and local structure of lanthanide were thermostable up to 800 °C.

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