Ligand “lock and fix” strategy provides stability to metal-organic frameworks for photodegradation processes

Metal-organic frameworks (MOFs) have editable structures and customizable functions. However, when most MOFs are exposed to water or humid air, their structures are degraded, which decreases the efficiency of water-based applications. Herein, we provide a ligand “lock and fix” post-synthetic modification strategy to create stable MOF in aqueous and photo-irradiation environments. We designed a cerium-based MOF (Ce-bpy) composed of cerium-oxo clusters and 2,2′-bipyridine-5,5′-dicarboxylate (bpy). In parallel, we constructed a stable MOF by functionalizing Ce-bpy with copper ions and 2,2′-bipyridyl. Calculations suggest that the modified MOF limits the inner rotational freedom of the ligands, increasing the rigidness and thus the aqueous stability. Furthermore, the stable MOF is used for both the photodegradation of tetracycline and phosphate detection. These findings show that the strategy could effectively enhance the resistance of MOFs to aqueous environments, allowing for water-based applications.