Recent advances in tailoring zeolitic imidazolate frameworks (ZIFs) and their derived materials based on hard template strategy for multifunctional applications

Zeolitic imidazolate frameworks (ZIFs), an important subfamily of metal-organic frameworks (MOFs), have been a hot topic as the porous structure nature, high specific surface area and abundant metal/metal compound active sites enables numerous applications in photo/electrocatalysis, gas storage, separation, and sensors etc. Also, ZIFs can serve as ideal precursors to synthesize versatilely functional materials based on the conversion of metal nodes and organic linkers. The microscopic morphology, size, and pore structure of ZIFs have a great influence on the applications. Therefore, it is important to design and synthesize ZIFs with different morphologies. Compared with direct nucleation in liquid phase, hard template strategy toward ZIFs provides a favorable opportunity to expand the microscopic morphology of ZIFs and their derivatives, from sphere, one-dimensional (1D) tube, twodimensional (2D) sheet and three-dimensional (3D) flower, etc. Several works have summarized the synthesis and applications of ZIFs and its derivatives. However, there is a scarcity of reviews about the preparation of the ZIFs by the template method in the last 5 years. Here, this review focuses on hard-template based strategies for designing ZIFs and their derived materials. We first introduce the basic principles of ZIFs synthesized by the template method. Then, we summarize the types of templates and their advantages for synthesis. The corresponding routes used to synthesize different structures of ZIFs are described in detail. The influence of ZIF composition and structure on their applications in typical fields is also discussed. Finally, we present some challenges for the synthesis of ZIFs by the template method. This review will guide future research on constructing ZIFs with appropriate templates to extend their properties and applications.