Exploring the Aggregative Growth of Nanoporous Zeolitic Imidazolate Framework ZIF-8

Abstract

Nucleation and crystallization have been proven to be the key steps for early stage formation of metal–organic framework nanoparticles. However, the growth mechanisms attributed to size and topology control at the later stages require more research. In this study, we provide new insight into an aggregative growth pattern observed for zeolitic imidazolate framework-8 (ZIF-8). Nanoscaled ZIF-8 was synthesized with an excess of organic ligands. After reaching a size limitation, ZIF-8 particles undergo an oriented attachment (OA) growth pathway to form clusters. Additional imidazole ligands as bridging agents facilitate the OA process by cross-linking smaller ZIF-8 particles. Adding a cationic surfactant disturbs the interfacial electrostatic interactions among those nanoparticles and reduced the growth rate of {100} faces. We envision that the work presented here will inspire the mechanism studies for other nanoporous crystals.