Structural engineering of POM-based composite materials: zeolite and silica as supports

Abstract

Polyoxometalates have emerged as pivotal inorganic catalysts for redox reactions, energy conversion, and environmental remediation. However, their practical utility is limited by solubility in polar media, aggregation, and recyclability challenges. Immobilizing polyoxometalates on porous supports—such as metal–organic frameworks, carbon materials, silica, and zeolites—could overcome these limitations. Zeolites could disperse and stabilize polyoxometalates under harsh conditions due to their ordered micropores (<1 nm), high surface areas (300–1000 m² g⁻¹), tunable acidity, and robust stability. Silica, featuring tunable mesopores (e.g., SBA-15, MCM-41) or disordered networks, offers versatile platforms for polyoxometalate immobilization. Surface functionalization of silica tailors host–guest interactions, improving cyclic stability. Advanced architectures integrating auxiliary components or featuring core–shell structures could be achieved with zeolite and silica as supports. This review presents an overview of recent advances in structural engineering of polyoxometalates/zeolite and polyoxometalates/silica composites, including synthesis methods (in situ encapsulation, impregnation, sol–gel, and surface functionalization) and several representative polyoxometalates/zeolite and polyoxometalates/silica composites. It also highlights future directions, such as designing catalysts with multiple functions and using advanced characterization techniques to elucidate the catalytic mechanisms of composite materials.