Rapid construction of hierarchically porous metal-organic frameworks by a spray-drying strategy for enhanced tannic acid adsorption

Metal-organic frameworks (MOFs) have attracted much attention owing to their tailored pore environment and surface functionality. However, most of the currently reported MOFs are confined to small pore sizes (<5 nm), limiting their practical applications. Here, a facile and versatile strategy for rapid construction of hierarchically porous MOFs (HP-MOFs) by spray-drying is reported, in which presynthesized nanosized MOFs (N-MOFs) can be assembled to form MOF microspheres with meso/macropores resulting from the interspace among closely arranged N-MOFs. This strategy enables the construction of multicomponent HP-MOFs with various functions. As a proof of concept, we show that the adsorption for tannic acid (TA) can be significantly enhanced using HP-MIL-101(Cr). Particularly, HP-MIL-101-30 (30 represents the primary nanoparticle size) exhibits a record-high adsorption capacity (1175 mg g(-1)), and the adsorption rate of HP-MIL-101-30 is increased by 50% compared to that of N-MIL-101-30. These findings have important implications for the rapid construction of HP-MOFs, which is beneficial for the adsorption of large molecules.