Engineering growth defects: a new route towards hierarchical ZSM-5 zeolite with high-density intracrystalline mesopores

Abstract

Hierarchical zeolites are promising solid acid catalysts for industrial processes and conversions of bulky molecules because they provide fast mass transfer along with size and shape selectivity; however, their synthesis always involves either complicated post-synthetic modifications or cost-intensive templates. In this work, engineering growth defects has been developed as a new and efficient strategy for preparing hierarchical ZSM-5 zeolite with high specific surface area and abundant uniform intracrystalline mesopores. This route only involved certain energy-efficient conditions, e.g., tender crystallization and mesotemplate-free conditions. Combining tender crystallization conditions with an optimal original Si/Al ratio (150–300) in a colloid synthesis system was found to be the key to successfully engineer the growth defects. Importantly, it even exhibited higher catalytic activities for benzaldehyde–alcohol condensation reactions than mesoporous ZSM-5 zeolite prepared using mesoscale templates.