Novel Fe₃O₄@SiO₂@Ag@Ni trepang-like nanocomposites: High-efficiency and magnetic recyclable catalysts for organic dye degradation

A facile step-by-step approach is developed for synthesizing the high-efficiency and magnetic recyclable Fe₃O₄@SiO₂@Ag@Ni trepang-like nanocomposites. This method involves coating Fe₂O₃ nanorods with a uniform silica layer, reduction in 10% H₂/Ar atmosphere to transform the Fe₂O₃ into magnetic Fe₃O₄, and finally depositing Ag@Ni core-shell nanoparticles on the L-lysine modified surface of Fe₃O₄@SiO₂ nanorods. The fabricated nanocomposites are further characterized by x-ray diffraction, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectroscopy. The Fe₃O₄@SiO₂@Ag@Ni trepang-like nanocomposites exhibit remarkably higher catalytic efficiency than monometallic Fe₃O₄@SiO₂@Ag nanocomposites toward the degradation of Rhodamine B (RhB) at room temperature, and maintain superior catalytic activity even after six cycles. In addition, these samples could be easily separated from the catalytic system by an external magnet and reused, which shows great potential applications in treating waste water.