Post-modified ionic metal-organic frameworks regulating the electronic states of Pd NPs to improve nitroaromatic selective catalysis

The selective hydrogenation of nitroaromatics faces challenges such as low selectivity and rapid deactivation of noble metal catalysts. In this study, 2–4 nm palladium nanoparticles (Pd NPs) were uniformly loaded into an amino-functionalized ionic metal-organic framework (IMOF) via an ion-exchange method, followed by post-modification with electron-withdrawing fluorine atoms. The introduced fluorine atoms effectively modulated the electronic states of Pd NPs and optimized the adsorption of polar functional groups on the catalyst surface, thereby significantly suppressing over-hydrogenation side reactions. The optimized Pd@IMOF-F catalyst achieved 99% conversion and > 99% selectivity in the hydrogenation of 4-nitrostyrene, with stable performance maintained over seven catalytic cycles. This work provides a novel strategy for precisely regulating the electronic states and local environments of catalytic active centers, offering significant theoretical and practical insights for the design of green chemistry and sustainable catalytic systems.