Stabilizing Palladium Nanopaticles On The Functionalized Magnetic SiO₂ Materials: Synthesis And Catalytic Application

In order to overcome the shortcomings of noble metal catalysts and to develop a highly active, stable, durable and easy separation of immobilized palladium catalysts, we use organic group functionalized magnetic materials as a carrier of noble metal catalysts in this paper. We use dif-ferent modification methods to develop the following two different series of magnetic SiO2 mate-rials supported palladium nanoparticles catalys, and conduct in-depth study of its catalytic activity and chemical stability.The magnetic Fe3O4 nanoparticles (NPs) were immobilized on the styrene and acrylic acid copolymers (carboxylated polystyrene spheres, PS) with the electrostatic adsorption. And then it wrapped in a thin layer of SiO2 on the surface and the template was removed after calcination, and the hollow magnetic mesoporous spheres (HMMS) was prapared.Then, HMMS was functional-ized by covalent binding of a Schiff base ligand, N,N’-bis(3-salicylidenam- -inopropyl)amine (salpr), and followed immobilization with Pd(0), thus HMMS-salpr-Pd (0) was prepared. The cat-alyst characterized by TEM, EDX, FT-IR, XRD, VSM, TGA and N2 adsorption-desorption. The novel catalyst exhibited a high activity in hydrogenation and Suzuki coupling reaction. Further-more it was easy to be recovered in a facile manner from the reaction mixture and recycled six times without any loss in activity.By co-precipitation method and sol-gel, we prepared Fe3O4 particles with silica wrapping, then the carriers were functionalized with aminopropyltrimethoxysilane and succinic acid chloride. The last, under the action of coordination and in-situ reduction of PdCl2, we prepared two kinds of catalyst. The catalysts were characterized by TEM, XRD, FT-IR, VSM and ICP. The catalysts shows high activity in the hydrogenation and Suzuki reactions. The newly developed catalysts were easily recovered and recycled and during recycling stages.