Magnetic Fe₃O₄ and Fe₃O₄@C core-shell nanostructures were prepared by the hydrothermal method and the Pt nanoparticles was in situ attached on Fe₃O₄@C to form Fe₃O₄@C/Pt nanocomposite. The TEM, SEM, FTIR and Raman spectroscopy were employed to characterize the surface morphology and composition. The catalytic activities of pure Pt nanoparticles (2 nm) and Fe₃O₄@C/Pt on the reaction of the transformation of 4-nitrophenol to 4-aminophenol in the presence of NaBH₄ were investigated. The possibility of recycling on the catalyst was explored by applying an external magnetic field. The results revealed that Fe₃O₄@C/Pt exhibited higher catalytic efficiency than that of pure Pt nanoparticles. It was mainly due to the synergetic effect that occurred at the interface of metals and Fe₃O₄@C support. The charge transfer from magnetic core to the Pt caused the increase of electron density on Pt and thus improved the reducibility of Fe₃O₄@C/Pt. The nanocomposite catalyst was recyclable for about 20 times.

Key words: Fe₃O₄ magnetic nanoparticles, platinum, core-shell structures, catalysis, recycling