“Green” synthesis of magnetic core–shell Fe₃O₄@SN–Ag towards efficient reduction of 4-nitrophenol

This work presented a novel, facile, cost-effective and environmentally friendly approach for the preparation of magnetic core–shell structured catalyst i.e. Fe₃O₄@SN–Ag (abbreviation of Fe₃O₄@SiO₂–NH₂–Ag). During the process of preparation, Ag nanoparticles were in situ generated with amino groups in the surface of Fe₃O₄@SN serving as green reductant and stabilizer in the absence of any additional toxic reductant or organic reagent. Magnetic core, Fe₃O₄, was easily prepared through solvothermal method. The subsequent coating and surface amino functionalization of SiO₂ was accomplished via one-pot sol–gel method, which was green and time-saving. What’s more, the resulting catalyst exhibited excellent catalytic property (the reaction was finished within 2 min) and reusability (reused at least seven times) in the reduction of 4-nitrophenol.