Polyoxometalate/metal–organic framework hybrids and their derivatives for hydrogen and oxygen evolution electrocatalysis

Transition metal–based materials have become significant family of electrocatalysts for hydrogen and oxygen evolution because of their low cost, various compositions and structures, and their excellent electronic transfer ability. Because of their tunable compositions and diverse structures, polyoxometalates (POMs) are promising catalytic components and are promising precursors for the fabrication of early transition metal–based materials, especially for Mo and W, for hydrogen and oxygen evolution electrocatalysis. By incorporating POMs into metal–organic frameworks (MOFs) , the target POM/MOF will promote the dispersion of POMs and increase the compositional and structural complexity of the derived materials. In this review, recent relevant research fruits focusing on POM/MOF composites and their derivatives (such as carbides, oxides, phosphides, sulfides, and selenides) are summarized. Their designable synthesis, structure modulation, and electrocatalytic performance in HER and OER are highlighted to figure out the structure-property relationship. The existing problems of POM/MOF materials and their derivatives in electrocatalysis are also discussed. Then we propose the future prospective, providing a brand new vision of design and development of other POM/MOF-based/derived advanced electrocatalysts for water splitting.