Zeolitic imidazolate framework-8
shares the same topology with
sodalite zeolite but consists of Zn nodes bridged by imidazolate linkers
to form a neutral open-framework structure. ZIF-8 has been recognized
as a unique molecular sieving material with a flexible framework enabling
interesting “gate-opening” functionality. Controlling
the crystal size and shape is crucial for regulating the structural
flexibilities and mass transport properties. The present study demonstrates
that an aqueous-system-enabled spray-drying process enables the shape
engineering of ZIF-8 with a hollow polycrystalline structure. It is
notable that our synthesis route produces an amorphous zinc complex
compound, which possesses a continuous random network partially with
crystalline fillers, after spray drying followed by an amorphous-to-crystal
transition via activation treatment using polar organic solvents.
The size of primary ZIF-8 crystals consisting of secondary polycrystals
depends on the kind of the organic solvent. The macro-/microscopic
structures of hollow polycrystalline ZIF-8 significantly structurally
enhanced the adsorption capacity and uptake rate. The large-scale,
rapid production and enhanced adsorption performances make this continuous
method a very promising candidate for industrial applications and
shaping of MOF
