Scalable synthesis of two-dimensional metal organic frameworks and insights into solvent-guided oriented attachment

Two-dimensional metal organic frameworks (2D MOFs) are a class of next generation materials for adsorbents,membranes and sensors; however, many 2D MOF synthesis methods lack the scalability and precision required for translation to industrial scales. Furthermore, the engineering of 2D MOF structures is challenged by complex environment-surface interactions that arise from their high anisotropy, thinness and functionally diverse surfaces. In this work we developed new understandings and methods of engineering such structures by using accelerated, high shear synthesis, and solvent exchange. With the recently developed annular flow microreactor we synthesized 2DMOFs more efficiently than conventional batch methods, by up to 5 orders of magnitude in terms of reactor space-time-yield. To accurately characterize particle size and dynamics in various organic solvents, we used liquid cell transmission electron microscopy. This technique not only visualized the oriented attachment of nanosheets, but also showed that the rate and direction of attachment is significantly influenced by solvent-surface interactions. These techniques and understandings provide rational bases for 2D MOF engineering and process design.