Synthesis of ZIF‐8 Hollow Spheres via MOF‐to‐MOF Conversion

We report herein the synthesis of ZIF-8 hollow spheres with uniform size and shell thickness from monodisperse MOF-5 cubes via the MOF-to-MOF conversion strategy. The ZIF-8 hollow spheres were obtained by reacting micron-sized MOF-5 cubes in the 2-methylimidazole solution under the optimized experimental conditions. Their chemical composition, crystallinity, porosity, and thermal stability were well characterized and their formation was investigated by time-dependent electron microscopy and X-ray diffraction analysis. The porous nature of MOF-5 and the stronger coordination interaction between 2-methylimidazole and Zn ions are believed to be responsible for the formation of the ZIF-8 hollow spheres.