Hierarchically structured metal–organic frameworks assembled by hydroxy double salt–template synergy with high space–time yields

Abstract

We report a facile, green, and versatile synthetic route that exploits hydroxy double salt (HDS)–template synergy to achieve hierarchically structured metal–organic frameworks (H-MOFs) with high space–time yields (STYs). Hierarchically structured HKUST-1 and ZIF-8 were synthesized using the cooperative template strategy within 30 min (crystallization time). The resulting MOF products exhibited multimodal, hierarchically porous structures with meso-/macropores interconnected with micropores, as revealed by scanning electron microscopy, transmission electron microscopy, N₂ adsorption–desorption isotherms, and pore size distributions. The porosities of the produced H-MOFs varied with the amount and type of template. The synergistic effect of the HDS and template on meso-/macropore generation was elucidated. The synergistic effect disclosed here dramatically extends the choice of templates for H-MOF synthesis at room temperature and pressure. Furthermore, the rapid synthetic method is readily scalable with an STY of up to 2366 kg m⁻³ d⁻¹, a new record for the synthesis of hierarchically structured HKUST-1. The green, versatile, and sustainable method developed in this work provides a new direction for the rapid synthesis of various H-MOFs with tuneable porosities and high STYs for a wide range of applications.