Understanding effect of wall structure on the hydrothermal stability of mesostructured silica SBA-15

Mesostructured silica SBA-15 materials with different structural parameters were prepared by varying the postsynthesis hydrothermal treatment temperature and adding inorganic salts. The hydrothermal stabilities of these materials in steam were systematically investigated using a variety of techniques including powder X-ray diffraction, transmission electron microscopy, nitrogen sorption and ²⁹Si solid-state NMR. The effect of the pore size, microporosity or mesoporosity, and wall thickness on the stability was discussed. The results show that all of the SBA-15 materials have a good hydrothermal stability under steam of 600 °C for at least 24 h.