Fabrication and characterization of Fe3O4@APTES@PAMAM-Ag highly active and recyclable magnetic nanocatalyst: Catalytic reduction of 4-nitrophenol

The surface of amine-fuctionalized magnetic nanoparticle was coated with polyamidoamine dendrimer via of alkylation of amine groups with methyl acrylate (Micheal addition route). Then silver nanoparticles were doped between the layers of dendrimer branches. The as-prepared nanocomposite is composed of a central magnetite core with a strong response to external fields, an interlayer of SiO2, polyamidoamine dendrimer (G1) and numerous highly dispersed Ag nanoparticles with a narrow size distribution. The crystallite size from XRD (9 ± 2 nm) and particle size from TEM analysis (11.6 ± 0.2 nm) are consistent with each other. The catalytic activity of nanocomposite was tested against 4-nitrophenol. It has well magnetic separability and excellent reusability without major loss and activity (it can be conveniently recycled from the reaction system by using a magnet) and no deactivation has been observed after at least 5 cycles of reaction.