All-inorganic POM cages and their assembly: A review

Searching for suitable methods to construct all-inorganic cage materials by using polyoxometalates (POMs) as secondary building units (SBUs) has been of great interest, because such materials not only exhibit fascinating cage-shaped structures and unique physicochemical properties derived from both cage architectures and POM clusters, but also have promising and practical applications in areas of molecule separation, guest recognition, molecular reactors, photocatalysis, environmental protection, and so on. In this review, the recent development in all-inorganic POM-based cage materials is summarized, including their assembly methods, structures, properties, and related applications. Moreover, the current challenges in the design and assembly of all-inorganic POM cages as well as the development potential of this area also discussed.