Shaping of Metal–Organic Frameworks: From Fluid to Shaped Bodies and Robust Foams

The applications of metal–organic frameworks (MOFs) toward industrial separation, catalysis, sensing, and some sophisticated devices are drastically affected by their intrinsic fragility and poor processability. Unlike organic polymers, MOF crystals are insoluble in any solvents and are usually not thermoplastic, which means traditional solvent- or melting-based processing techniques are not applicable for MOFs. Herein, a continuous phase transformation processing strategy is proposed for fabricating and shaping MOFs into processable fluids, shaped bodies, and even MOF foams that are capable of reversible transformation among these states. Based on this strategy, a cup-shaped Cu-MOF composite and hierarchically porous MOF foam were developed for highly efficient catalytic C–H oxidation (conv. 76% and sele. 93% for cup-shaped Cu-MOF composite and conv. 92% and sele. 97% for porous foam) with ease of recycling and dramatically improved kinetics. Furthermore, various MOF-based foams with low densities (<0.1 g cm^–3) and high MOF loadings (up to 80 wt %) were obtained via this protocol. Imparted with hierarchically porous structures and fully accessible MOFs uniformly distributed, these foams presented low energy penalty (pressure drop <20 Pa, at 500 mL min^–1) and showed potential applications as efficient membrane reactors

Facile Fabrication of Multifunctional Metal–Organic Framework Hollow Tubes To Trap Pollutants

Pollutant treatment is critical in modern society and often requires tedious workup and expensive facilities. By virtue of structural diversity and tunability, metal–organic frameworks (MOFs) have shown promise in pollutant control. We herein report a powerful templated freeze-drying protocol for the fabrication of multifunctional MOF hollow tubular structures for both air and liquid contaminants filtration. Various hollow tube systems (e.g., “Janus”, “coaxial” and “cellular”) are produced. Specially, a multilayer coaxial MOF hollow tube is prepared for highly efficient capture of mixed inorganic–organic liquid contaminants with >94% filtration efficiency. Further, a “cellular” hollow tube with low pressure-drop (12 Pa, 10 cm s^–1) is applied in particulate matter filtration with high efficiency (>92%). Given the rich structural and functional diversities, this protocol might bring MOFs into industrial applications to remediate environmental problems