Fe oxide core/Au shell nanoparticles were prepared by the reduction of Au3+ onto the surfaces of Fe oxide nanoparticles and characterized by scanning electron microscopy(SEM). The results reveal that the prepared core/shell nanoparticles were covered by Au shell and the surfaces of the core/shell particles are jagged after the initial addition of Au3+. Surface enhanced Raman scattering(SERS) activities of these magnetic nanoparticles were studied by using pyridine(Py) as a probe molecule after a magnet was used to concentrate the colloid. It was found that the SERS intensity depends on the Au shell thickness of the core/shell nanoparticles and strengthens with the increasing shell thickness. The detection limit for Py can be very low when the magnetic Fe oxide core/Au shell nanoparticles were used and even down to 10-7 mol/L.
AucoreCoshell nanoparticles with different shell thicknesses were prepared by using chemical reduction method and characterized by scanning electron microscopy（SEM） and cyclic voltammetry（CV）. The results reveal that the prepared core-shell nanoparticles were covered by Co shell and exhibited the similar electrochemistry property with the Co nanoparticles surface. Surface enhanced Raman spectroscopy（SERS） activities of these nanoparticles were studied by using pyridine as a probe molecule. It was found that the SERS intensity depended on the Co shell thickness of the core-shell nanoparticles and was weakened with the increasing shell thickness. The SERS intensity of these AucoreCoshell nanoparticles is found to be about twenty times higher than that obtained on an electrochemically roughened cobalt electrode.
