Synthesis of gold-coated iron oxide nanoparticles

A microemulsion method has been used for the synthesis of iron oxide nanoparticles and its aqueous stabilization. Iron oxide nanoparticles of 9±2 nm in size were then coated with gold in a second step. For this purpose HAuCl4 was reduced employing glucose as a reducing agent. The mild conditions promote the reduction of Au ions adsorbed onto the γ-Fe2O3 particles in order to ensure a controlled shell growth of gold, and avoiding the formation of new gold nuclei. Different molar ratios of HAuCl4/glucose were investigated. The obtained core–shell structures have been characterized by TEM, UV spectroscopy, XRD and Magnetometry measurements.