Palladium-containing magnetic UiO-66-NH2 as a highly powerful and recoverable nanocatalyst for the reduction of nitrobenzenes.

Abstract

Magnetically recoverable porous materials with tunable surface chemistry are of growing interest for heterogeneous catalysis due to their ease of separation, structural versatility, and high surface accessibility. However, integrating multiple functional components into a single stable and reusable catalytic platform remains a significant challenge. In this study, the design and synthesis of a hierarchical nanocomposite, Fe₃O₄@MCM-41@UiO-66/SB-Pd, through a stepwise functionalization approach are reported. The strategy integrates a magnetic Fe₃O₄ core, mesoporous silica, a microporous UiO-66-NH₂ framework, and a Schiff base-coordinated Pd complex to yield a structurally ordered and catalytically active nanocomposite. The resulting nanomaterial exhibited a high surface area (249.1 m² g^-1), hierarchical porosity, thermal stability, and superparamagnetic behavior. Comprehensive characterization confirmed the successful incorporation of all functional groups while maintaining crystallinity. The Fe₃O₄@MCM-41@UiO-66/SB-Pd nanocomposite demonstrated high catalytic efficiency for the reduction of nitroarenes under mild conditions, along with excellent reusability. These results highlight a promising approach for designing hybrid catalytic materials with hierarchical porosity, enhanced stability, and practical recyclability for environmentally relevant transformations.