Porous Solids for Energy Applications: Clathrate hydrates, Metal-organic frameworks (MOF) and Covalent-organic frameworks (COF)

Although solids are usually quite dense, in certain special cases the building blocks form an open structure with cavities where guest molecules can be encaged. The amount of guest species within a unit volume of the solid can be surprisingly large, which opens the door to the possibility of storing gas molecules within the solid framework. This is the case for clathrate hydrates, where rather open solid framework structures of water are able to host molecules within different size ranges (methane, carbon dioxide, hydrogen), and organic-frameworks (MOF/COF), where an open solid structure is formed either by the reaction between a metal ion or oxocluster and an organic ligand (MOF) or two monomers of a certain symmetry (COF). The chemistry and size of these cavities can be tuned for a particular application.

These systems raise interesting challenges both from a fundamental point of view, concerning the balance of intermolecular interactions leading to their formation and stability, self-assembly, and crystal structure, and from a practical point of view, regarding their application as a natural energy resource (methane hydrates), hydrogen storage materials (in clathrates and MOF/COF), carbon dioxide sequestration materials (hydrates/MOF/COF), environments for catalysis and for the separation of gases. This special topic issue will focus on the underlying chemical physics characteristics of these types of porous solids.