Palladium nanoparticles immobilized on core-shell magnetic fibers as a highly efficient and recyclable heterogeneous catalyst for the reduction of 4-nitrophenol and Suzuki coupling reactions

In this study, a novel core-shell magnetic fibrous nanocatalyst, Pd/Fe3O4@SiO2@KCC-1 with easily accessible active sites and a convenient recovery by applying an external magnetic field, was successfully developed. Fe3O4@SiO2@KCC-1 was functionalized with amino groups which act as robust anchors so that the palladium nanoparticles (Pd NPs) with an average diameter of about 4 nm were well-dispersed on the fibers of Fe3O4@SiO2@KCC-1 without obvious aggregation. The synthesized Pd/Fe3O4@SiO2@KCC-1 nanocatalyst exhibited excellent catalytic activity in the reduction of 4-nitrophenol by sodium borohydride, and the Suzuki cross coupling reactions of aryl chlorides with aryl boronic acids due to the easy accessibility of the active sites. Furthermore, the Pd/Fe3O4@SiO2@KCC-1 nanocatalyst was conveniently recovered by a magnet and could be reused for at least five cycles without significant loss in activity, thus confirming its good stability. Therefore, the abovementioned approach based on core-shell magnetic fibrous Fe3O4@SiO2@KCC-1 provided a useful platform for the fabrication of Pd NPs based catalysts with easy accessibility, superior activity and convenient recovery.