Synthesis of naked plasmonic/magnetic Au/Fe ₃ O ₄ nanostructures by plasmon-driven anti-replacement reaction

In this study, naked Au(core)/Fe 3 O 4 (shell) hybrid nanostructures are rapidly synthesized by a plasmon-driven anti-replacement reaction. The Au nanoparticles are prepared by pulsed laser ablation in water. The mixture of Au nanoparticles and FeCl 3 solution is irradiated under a laser with a specific wavelength. The Fe 3+ ions are reduced to low valence species by the ‘hot electrons’ in Au, and form the Fe 3 O 4 spindles on the surface of Au nanoparticles. The Au nanoparticles are synchronously oxidized to Au + and Au 3+ ions by the ‘hot holes’. The saturation magnetization and coercivity of Fe 3 O 4 spindles are 48.7 emu g −1 and 218.9 Oe, respectively. Our work provides a facile route to obtain the naked Au/Fe 3 O 4 plasmonic/magnetic nanostructures.