The Solvent Induced Inter‐Dimensional Phase Transformations of Cobalt Zeolitic‐Imidazolate Frameworks

Abstract Studying inter‐dimensional phase transitions of zeolitic‐imidazolate frameworks (ZIFs) is essential for developing strategies in controlling morphology and properties. Herein, the inter‐dimensional topotactic phase transformations of 3D ZIF‐67 to 2D ZIF‐L are investigated in detail by employing a simple and efficient solvent‐induced growth method. In addition to ZIF‐67 and ZIF‐L, a series of novel core–shell composites of ZIF‐67@ZIF‐L, with unprecedented morphologies, are also obtained and well‐defined. The different behaviors of the amine hydrogen of 2‐MIM in the solvents play a pivotal role for inter‐dimensional phase transformations, and in combination with the concentration of 2‐MIM, the 2D to 3D phase transformations are also revealed. The findings are very beneficial for morphological design of the ZIFs, along with exploration of the corresponding properties. Impressively, Co‐ZIFs exhibit interesting tunable CO 2 adsorption behaviors with the phase evolution, which might bring broader understanding for designing CO 2 detection and adsorption devices.