Shape control of core-shell MOF@MOF and derived MOF nanocages via ion modulation in a one-pot strategy

Core-shell MOF@MOF structures are good candidates for the design of diverse multifunctional materials with intriguing properties. Conventional seed-induced growth procedures to create MOF@MOF usually suffer from limitations including the unavoidable nucleation/growth of the shell MOF in solution and the inevitable agglomeration of seeds. For the first time, an ion-modulation (Fe3+ as the indicator) strategy is demonstrated to realize one-pot synthesis of monodisperse MOF@MOF composed of two distinct Prussian blue analogues (PBAs). It utilized a finite amount of Fe3+ to induce a partial phase transition and generate new PBA nanoparticles epitaxially growing on the original PBA core. The as-prepared PBA@PBA with a distinct morphology, readily tunable by controlling the dose of dopant ions, can serve as a template for the creation of PBA nanocages with uncommon and tunable shapes for efficient phenol scavenging. The findings here pave the way for the rational design of MOFs with high complexity, good structural flexibility, and desirable activity.