Recent advances in bimetallic metal-organic frameworks (BMOFs): synthesis, applications and challenges

Bimetallic metal-organic frameworks (MOFs) possess two different metal ions as nodes in their molecular frameworks. They are prepared by either one-pot syntheses, wherein different metals are mixed with suitable ligands and linkers, or by adopting post-synthetic modifications by soaking a monometallic MOF in a concentrated solution of a different (but compatible) metal ion. These bimetallic MOFs exhibit synergistic effects and enhanced properties compared to their monometallic counterparts, such as improved adsorption selectivity, selective catalysis and structural stability. Certainly, there are still many open challenges, given that bimetallic MOFs suffer from the typical drawbacks of MOFs, including high moisture sensitivity, easy oxidation due to their varying oxidation states, and possible metal leaching in liquids. In the present perspective, progress in the research on the synthesis and properties of bimetallic MOFs has been reviewed systematically, describing the synthetic strategies adopted to prepare targeted bimetallic MOFs and their applications in gas adsorption, catalysis, energy storage and conversion, and luminescence sensing. Additionally, the challenges facing the synthesis of stable and robust bimetallic MOFs have been discussed with a final outlook on their further development prospects.