Modulating Ce₆ Nodes of Ce-MOFs for Boosting the Photocatalytic Decarboxylative Oxygenation of Carboxylic Acids

Tuning the microenvironments of metal nodes in metal-organic frameworks (MOFs) is crucial for optimizing their photocatalytic performance, but it remains challenging. Herein, we report a benzoic acid (BA) modulator-assisted strategy to regulate the coordination microenvironment of Ce₆ nodes in Ce-based MOFs (Ce-1,3,5-benzenetribenzoate, Ce-BTB), thereby enhancing their photocatalytic activity toward the decarboxylative oxygenation of carboxylic acids. By variation of the BA amount, a series of Ce-BTB nanosheets with controlled crystallinity, morphology, and coordination microenvironment were obtained. The optimized Ce-BTB-60 exhibits superior visible-light-driven (425 nm) performance for converting arylacetic acids to aldehydes under O₂ atomosphere, attributed to promoted ligand-to-metal charge transfer (LMCT), suppressed charge recombination, and improved interfacial charge transport. Detailed radical trapping experiments and density functional theory (DFT) calculations reveal that the coordinated BA and mixed-valence Ce centers facilitate substrate binding and LMCT-driven radical generation. This work highlights coordination microenvironmental modulation as an effective strategy for designing MOF-based photocatalysts for organic transformations.