Facile method for preparing gold coated iron oxide nanoparticles

Abstract

An improved ‘seed mediated growth’ method for preparing gold coated iron oxide nanoparticles is demonstrated herein. This method involves two steps. First, the seed gold nanoparticles were affixed to the surface of the iron oxide nanoparticles through amino groups. Second, by reducing HAuCl4 with glucose in the aqueous solution, the seed gold nanoparticles became larger, and a gold shell was formed on the surface of the magnetic nanospheres ultimately. These Au–Fe3O4 nanoparticles were characterised by X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and vibration sample magnetometer. The characterisation results showed that this method can prepare gold shell coated iron oxide nanoparticles efficiently, and the prepared superparamagnetic hybrid Au–Fe3O4 nanoparticles possessed a saturation magnetisation of ∼27·9 emu g−1.