Substantially reduced crystallization temperature of SBA-15 mesoporous silica in NaNO3 molten salt

• Cristobalite was fabricated by a molten salt method using SBA-15 as precursor.
• The preparation temperature was only 500 °C.
• It is a promising method to realize the low temperature crystallization of silica..

This paper described a simple molten salt method to realize the crystallization of SBA-15 mesoporous silica at a relative low temperature of 500 °C under atmospheric pressure. Scanning electron microscopy (SEM), high-magnification transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrometer were employed to characterize the morphology, crystal structure of prepared products in detail. The SEM results showed that cristobalite nanoparticles of SBA-15 were successfully obtained in NaNO3 molten salt at a relatively low temperature compared with former approaches, which was mainly ascribed to the tiny dosage of sodium ions and the surfactant of P123 in SBA-15 crystallization system.