Synthesis of ordered cubic mesoporous ZrMCM-48 molecular sieve with aid of fluoride ions

Using cetyltrimethyl ammonium bromide (CTAB) as the template and tetraethyl orthosilicate (TEOS) as silica source, ordered cubic mesoporous ZrMCM-48 molecular sieves were synthesized by addition of sodium fluoride in hydrothermal crystallization process. The structure and property of the calcined sample were characterized by XRD, TEM, XPS, and N2 physical adsorption, respectively. The effect of crystallization time, crystallization temperature and F−/Si molar ratio on synthesis process of sample was systematically investigated. Also, the different molar ratios of Si/Zr on textural properties of ZrMCM-48 samples were also evaluated. The results show that the optimum synthesis conditions of cubic ZrMCM-48 sample are the following: crystallization temperature is 120 °C, crystallization time is 24 h and F−/Si ratio is 0.1. A small amount substitution of Zr ions for Si4+ in the framework of MCM-48 did not significantly change the textural properties while the higher Zr content incorporated leads to decrease of the surface area and deterioration of structural regularity.