In Situ Assembly of Zeolite Nanocrystals into Mesoporous Aggregate with Single-Crystal-Like Morphology without Secondary Template

The formation of zeolite crystal its subsequent assembly into a mesoporous aggregate by enhancing the zeolite nucleation rate was demonstrated. ZSM-12 was selected that has micropores that are slightly larger and during the synthesis of ZSM-12 crystals and a mesoporous aggregate of ZSM-12 nanocrystals with a morphology similar to common ZSM-12 was obtained. The hydrothermal stability of ZSM-12 was tested by refluxing in boiling water for 120 hours with a sample-to-water ratio of 1:10 and by increasing the crystallization time to 8 days. The meso- and microstructure of mesoporous ZSM-12 was found to be stable during the treatments that was confirmed by powder X-ray diffraction images and scanning electron microscopy. The results indicate that the mesoporous ZSM-12 is highly hydrothermally stable that is important for the industrial catalytic applications.