Highly dispersed Pd nanoparticles supported by magnetically separable Fe₃O₄@ SiO₂ nanotube for catalytic hydrogenation of nitroaromatics

Selective hydrogenation of nitroaromatics is a crucial industrial reaction, but there are still challenges in developing nanocatalysts with stable active centers, yet easily recyclable characteristics. Here, a magnetically separable Pd/Fe₃O₄@SiO₂ nanocatalyst was prepared through the seeding growth of silica on the Fe₃O₄ nanocrystal cluster (NC) followed by in situ reduction of Pd nanoparticles (NPs) on the amino group modified Fe₃O₄@SiO₂ nannotube (NT). The nanocatalyst showed good activity and stability in the hydrogenation of a series of nitroaromatics as the Pd NPs were highly dispersed on the nanotubes. Meanwhile, it could be easily separated from the reaction solution and well-redispersed in the solvent for the next-round reaction due to the superparamagnetic property of the Fe₃O₄ NC and the good dispersibility of silica in many organic solvents. The magnetically separable nanocatalyst combined the high activity of the nanocatalyst and the convenient separation of a traditional heterogeneous catalyst, which effectively promote the practical application of nanomaterials in catalysis.