Sodium carbonate-assisted synthesis of hierarchically porous single-crystalline nanosized zeolites

Hierarchically porous single-crystalline nanosized zeolites as heterogeneous catalysts show great potential in fine chemistry because they offer more rich hierarchically porous channels for the mass transfer and molecular diffusion. However, the synthesis of hierarchically porous nanosized zeolites generally requires the assistance of templates acting as the mesoporogens, which limits its popularity. Herein, we report a one-pot and template-free synthesis of hierarchically porous single-crystalline nanosized zeolite beta only by introducing sodium carbonate in precursor solution. The resulted sample features the extraordinary properties, including the uniform nanocrystal (200-300 nm), high pore volume (0.65 cm(3) g(-1)) and the hierarchical pore-size distribution (e.g., 2-8 and 90-150 nm). After slicing processing, it is interestingly found that a large number of interconnected mesopores penetrate throughout whole material, which enables the hierarchically porous nanosized zeolite beta remarkably superior catalytic activity than the conventional zeolite beta in condensation of benzaldehyde with ethanol at room temperature. More importantly, this one-pot sodium carbonate-assisted synthetic strategy is highly versatile, which has also been successfully developed to synthesize hierarchically porous nanosized single-crystalline zeolites ZSM-5 and TS. (C) 2017 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.