Integration of Metal-Organic Framework and Clay Toward Functional Composite Materials

Metal-organic frameworks (MOFs) have become increasingly important as a class of porous crystalline materials because of their diverse applications. At the same time, significant progress has been achieved in the field of MOF-based composite materials toward novel applications based on the synergistic role of two or more different components. Clay materials have been explored recently in MOF chemistry for the synthesis of MOF-clay composites, which are a new class of functional materials synthesized by a cooperative combination of MOF with clay. Such composites have evolved only in the recent past, with important functions and applications, such as enhanced gas storage and separation, CO2 capture and conversion, catalysis, drug delivery, and water-harvesting. Notably, the typical shortcomings of MOFs, like moisture sensitivity, poor water dispersibility, poor thermal and chemical stability, and processability, could be overcome by developing novel MOF-clay composites. This article provides a concise overview of MOF-clay composites and their applications in various fields that would drive the interest of researchers to explore the emerging field of MOF-clay chemistry. In the initial sections, we classified the clays that have been used in MOF chemistry and briefly discussed their structures and chemistry. We also presented the advantages of MOF-clay composites and discussed their synthetic methodologies. In the later sections, we classified the different MOF-clay composites based on the clay and presented some representative examples of such composites showing unique properties and applications. Finally, the development in this field is summarized, and the future scope of such composites is discussed.