Covalently modified polyoxometalates (POMs), which benefit from the synergistic effect between POMs and covalently grafted moieties, have received increasing attention in various fields. Recent studies on the covalently modified POMs mainly focus on the function-directed POMs assemblies. In this review, we summarized the latest progress (2017-2022) of covalently modified POMs from functional perspective, which can be classified as assembly chemistry, photochemistry, electrochemistry, homogeneous/heterogeneous catalysis and biological application.The roles of POMs and covalently grafted moieties in these hybrids, especially the rational design for the specific application were considered and emphasized.

Polyoxometalates (POMs) are widely used in catalysis, energy storage, biomedicine, and other research fields due to their unique acidity, photothermal, and redox features. However, the leaching and agglomeration problems of POMs greatly limit their practical applications. Confining POMs in a host material is an efficient tool to address the above‐mentioned issues. POM@host materials have received extensive attention in recent years. They not only inherent characteristics of POMs and host, but also play a significant synergistic effect from each component. This review focuses on the recent advances in the development and applications of POM@host materials. Different types of host materials are elaborated in detail, including tubular, layered, and porous materials. Variations in the structures and properties of POMs and hosts before and after confinement are highlighted as well. In addition, an overview of applications for the representative POM@host materials in electrochemical, catalytic, and biological fields is provided. Finally, the challenges and future perspectives of POM@host composites are discussed.

The Anderson-type polyoxometalates (POMs) are one of the most important and widely developed groups of the POMs family. The covalent functionalization of Anderson POMs have attracted extensive attention and facilitated...