Facile synthesis of hierarchical porous metal-organic frameworks with enhanced catalytic activity

Abstract

The development of a general method for the facile synthesis of hierarchical porous metal–organic frameworks (H-MOFs) with tunable porosities is important because of their widespread applications. Herein, through the ingenious use of different neutral organic amines as templates, we report the development of a green and versatile method to synthesize three H-MOFs (Cu-BTC, ZIF-8, and ZIF-90) with tunable morphologies and porosities. The selected neutral amine template molecules deprotonated organic ligands and facilitated the formation of H-MOFs while guiding the formation of meso- and macropores. These high quality as-synthesized H-MOFs possessed micro-, meso-, and macropore hierarchical structures and high thermal stability after the amine templates were removed by simple washing and drying. The as-prepared Cu-BTC H-MOFs exhibited more than 2 times higher activity than conventional microporous Cu-BTC in catalyzing Henry reaction. Our facile strategy establishes a green and general route to synthesize a large variety of H-MOFs for various applications, particularly when large molecules or biomolecules are involved.