Multifunctional magnetic core-shell dendritic mesoporous silica nano spheres decorated with tiny Ag nanoparticles as a highly active heterogeneous catalyst

In present work, a multifunctional magnetic core-shell dendritic silica nanocatalyst Fe3O4@SiO2@Dendritic-SiO2-NH2-Ag with easy accessibility of active sites and convenient recovery was successfully fabricated by an oil-water biphase stratification coating strategy, and characterized by transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N-2 adsorption-desorption, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The as-synthesized nanocatalyst Fe3O4@SiO2@Dendritic-SiO2-NH2-Ag displayed excellent catalytic activity for the catalytic reduction of 4-nitrophenol and 2-nitroaniline using sodium borohydride in aqueous solution at room temperature due to easy accessibility of active sites. Interestingly, the novel catalyst could be conveniently recovered by magnetic separation from the reaction system and recycled for at least five times without significant loss in activity. These results indicate that the above mentioned approach based on magnetic core-shell dendritic silica Fe3O4@SiO2@Dendritic-SiO2 provided a useful platform for the preparation of noble metal nanocatalysts with easy accessibility, excellent catalytic activity and convenient recovery. (C) 2015 Elsevier B.V. All rights reserved.