New Hybrid Nanomaterials Derived from Chemical Functionalization of Clicked Graphene Oxide / Magnetite Nanocomposite with Peroxopolyoxotungstate Species

Two new hybrid nanomaterials were developed by immobilization of peroxopolyoxotungstate on the surface of clicked graphene oxide/magnetite nanocomposite. First, graphene oxide/magnetite nanocomposite was produced through the thiol-ene click reaction of graphene oxide with mercaptopropyl- functionalized magnetite nanoparticles in the presence of benzoyl peroxide. Then, the prepared graphene oxide/magnetite nanocomposite was functionalized with (3-aminopropyl) triethoxysilane or cysteamine hydrochloride as spacer groups for the subsequent immobilization of peroxopolyoxotungstate species. The prepared hybrid nanomaterials exhibited high activities and complete selectivities (>99%) in the epoxidation of olefins with H2O2 under mild reaction conditions. In addition, they can be magnetically separated and reused several times without remarkable loss of catalytic efficiency.