Room temperature fabrication of oriented Zr-MOF membrane with superior gas selectivity with zirconium-oxo cluster source

Rational structural design and engineering of MOF membranes is particularly promising for energy-efficient gas separation. Preferred orientation manipulation delegates an effective approach to eliminate intercrystalline defects and therefore, improve their separation performance, while room-temperature (RT) synthetic protocol is quite beneficial to foster their industrial batch production. Nevertheless, it remains challenging to fabricate highly oriented MOF membranes at RT; simultaneously, the density of defective sites in the framework, which is assumed to exert significant influence on the separation performance relying on high affinity-interactions between guest molecules and coordinatively-unsaturated open metal sites, should be deliberately tailored. In this study, we achieve RT synthesis of highly (111)-oriented UiO-66 membrane exhibiting high defect density in the framework through employing Zr6O4(OH)4(OAc)12 clusters as zirconium source during epitaxial growth. Prepared UiO-66 membrane manifests an ideal CO2/N2 selectivity of 46.2, which represents the highest value among all pure MOF membranes tested in comparable operating conditions. It is anticipated that the above protocol can be further expanded for facile and mild preparation of state-of-the-art MOF membranes.