An unusual hierarchical ZSM-5 microsphere with good catalytic performance in methane dehydroaromatization

In this paper, a novel hierarchical ZSM-5 microsphere (simplified as ZSM-5-MS hereafter) of about 3 μm, which is assembled by many French fries-like crystals (in shape of French fries) of about 100 nm in width, was synthesized by using SBA-15 as the silica source. ZSM-5-MS exhibited a unique geometrical shape which was entirely distinct from the conventional MFI shape. The N2 adsorption isotherm suggested that the ZSM-5-MS had a uniform mesopores of 15 nm with a tail up to 45 nm. The ZSM-5-MS was modified to form a Mo/HZSM-5-MS catalyst which exhibited good catalytic performance in methane dehydroaromatization (MDA) due to the presence of both micropores and mesopores. A time trial study was carried out by SEM, XRD and TEM analysis for the insight into the growth of the obtained ZSM-5-MS. A growth model via self-assembly combined with crystallization process was proposed based on the time trial observations. The demonstrated route may be extended to synthesize other types of zeolites with unusual structure and properties.