Synthesis of Micropore/Mesopore Composite Materials

The objective of this study was to synthesize micropore-mesopore composite materials by two-step crystallization. The colloidal MFI was first synthesized using a structure-directing agent tetrapropylammonium hydroxide as a template in the first step. This colloid was then self-assembled to form mesoporous structure by using cetyltrimethylammonium bromide as a surfactant. These materials were characterized by powder X-ray diffraction, nitrogen sorption, SEM and TEM. Due to the thick walls produced, it cannot sustain the local strain caused by the crystallization: the mesostructure is collapsed upon heating. The mixed phases of MFI and MCM-41 were obtained by optimizing the synthesis times and reaction temperatures.