Promoting Carrier Separation in W 10 O 32 4– -Doped POM@MOF Composites for Photocatalytic Oxidative Coupling of Amines

The integration of polyoxometalates (POMs) into metal-organic frameworks (MOFs) to construct composite photocatalysts represents a promising strategy for organic synthesis. The photosensitive W10O324- clusters (noted as W10) were assembled with the La-MOF framework at the molecular level, successfully constructing a series of W10@MOF composites. These materials not only endow La-MOF with visible-light absorption capacity but, more importantly, significantly promote the separation and migration efficiency of photogenerated electron-hole pairs. In the photocatalytic amine oxidation coupling reaction, W10@MOF-4, with the largest W10 loading amount, exhibits excellent catalytic performance. Under mild conditions and without the need for an external oxidant, it achieves a benzylamine conversion rate of 98% and an imine selectivity of >99%, outperforming the single component and demonstrating a significant synergistic catalytic effect. Through systematic photoelectrochemical characterization, including photocurrent response, electrochemical impedance, and solid ultraviolet diffuse reflection analysis, it was confirmed that the introduction of W10 effectively regulated the material's energy band structure and significantly enhanced the interface charge separation efficiency as an electron capture center, providing a key mechanism basis for its outstanding photocatalytic performance.