A General Strategy for Instantaneous and Continuous Synthesis of Ultrasmall Metal–Organic Framework Nanoparticles.

Ultrasmall metal–organic frameworks (MOFs) may generate unique properties to expand the scope of applications. However, the synthesis is still a great challenge. Herein, we propose a strategy to synthesize ultrasmall MOFs by high gravity technology. With the aid of tremendous intensification of molecular mixing and mass transfer in high‐gravity field, six typical MOFs were obtained instantaneously in a continuous way. These samples are monodispersed with sub‐5 nm in size, smaller than the previously reported values and even close to the length of one crystal unit cell. As a proof‐of‐concept, catalytic activity for Knoevenagel reaction can be significantly enhanced using ultrasmall ZIF‐8. Conversion time of benzaldehyde was decreased by 94 % or 75 % compared to those using conventional or hierarchically porous ZIF‐8. More importantly, this approach is readily scalable with the highest space‐time yield for nano‐MOFs, which may promote the convenient synthesis and practical applications of ultrasmall MOFs in large‐scale. [ABSTRACT FROM AUTHOR]