Synergistic catalysis in POM@MOF and POM@COF composites: Emerging platforms for catalytic oxidation of sulfur-containing compounds

The catalytic oxidation of sulfur-containing compounds constitutes a pivotal research frontier with broad implications across biomedicine, environmental remediation, and chemical defense. Polyoxometalates (POMs), well-defined anionic metal–oxygen clusters exhibiting tunable redox activity, high acidity and structural robustness, represent promising molecular catalytic units for selective sulfur oxidation. Yet their practical application is frequently hampered by, aggregation and limited recoverability under reaction conditions, particularly in polar media. Porous framework materials, notably metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), offer structurally precise, modular scaffolds for the spatial confinement and stabilization of POMs. Host–guest composites engineered via encapsulation within framework cavities or channel walls not only suppress POM degradation and leaching but also synergistically enhance active-site accessibility, substrate diffusion and orientation, and interfacial charge-transfer kinetics. Existing reviews predominantly focus on single host systems or specific applications (e.g. only fuel oxidative desulfurization), failing to systematically encompass all three core research fields. This review comprehensively summarizes recent advances in POM@MOF and POM@COF composites in the fields of bioactive sulfide synthesis, fuel desulfurization and chemical warfare agent purification. The intrinsic correlations between host-guest interactions and catalytic performance, stability, as well as reaction mechanisms are discussed, and the future development directions in this field are prospected, aiming to facilitate the industrial application of related technologies.