Synthesis of metal–organic framework microrings via an anisotropic growth-etching approach

Abstract

Design of metal–organic frameworks (MOFs) with elaborate structural features is of great significance for their applications with improved performances. In this work, we report the construction of unique zinc-based zeolite imidazole framework (ZIF-8) microrings via an anisotropic growth-etching route. The synthesis relies on the anisotropic deposition of ZIF-8 crystals on the edges with coordinatively unsaturated Zn²⁺ of leaf-like ZIF (ZIF-L) nanosheets and subsequent selective etching of alkaline unstable ZIF-L. Furthermore, functional carbon materials with a ring-like structure can be prepared by pyrolysis of ZIF-8 microrings as precursors, exhibiting enhanced oxygen reduction reaction performance compared to the traditional ZIF-8 derived counterparts. Our work may pave the way for the design of MOFs with sophisticated micro/nanostructures.