Hollow metal-organic framework polyhedra synthesized by a CO2-ionic liquid interfacial templating route

We proposed for the first time a CO2-ionic liquid (IL) interfacial templating route for the production of hollow MOF microparticles. By adding the gaseous CO2 into IL phase under stirring, a large number of CO2 bubbles are generated, which provide numerous CO2-IL interfaces, serving as the nucleation or agglomeration centers for the MOF nanocrystals. By this strategy, the hollow and mesoporous Zn-BTC (BTC: 1,3,5-benzenetricarboxylic) tetrahedroids were fabricated. The morphologies of the Zn-BTC polyhedra can be easily controlled by CO2 pressure. The as-synthesized Zn-BTC hollow microparticles have shown potential applications in gas separation and catalysis. Furthermore, the CO2-IL interface templating approach has been successfully applied to the fabrication of microsized Zn-BDC (BDC: 1,4-benzenedicarboxylic) hollow prisms.