Highly dispersed Pd nanoparticles supported by magnetically separable FeO@ SiO 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/FeO@SiO nanocatalyst was prepared through the seeding growth of silica on the FeO nanocrystal cluster (NC) followed by in situ reduction of Pd nanoparticles (NPs) on the amino group modified FeO@SiO 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 FeO 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.