Tackling orientation of metal-organic frameworks (MOFs): The quest to enhance MOF performance

As the structure and properties of anisotropic metal–organic frameworks (MOFs) vary with certain directions in space, controlling the orientation of these MOFs allows full advantage to be taken of their anisotropic properties. Not surprisingly, the preparation of oriented anisotropic MOFs, has drawn great attention in the past decade. In this review, we systematically summarized the strategies utilized for the preparation and growth of oriented MOFs, highlighting the possibilities of each synthetic approach as well as the challenges they have to overcome. Herein, we have also explored the orientation of MOF-on-MOF hybrids. Finally, we have presented the advantages of oriented MOF crystals over their randomly oriented counterparts in different applications, including adsorptions, separations, catalysis, sensing, energy storage, etc. We hope this review shows the tremendous possibilities of oriented MOFs and helps the reader better comprehend oriented MOF synthesis, properties, and applications.