Post-treatment Method for the Synthesis of Monodisperse Binary FePt-Fe3O4 Nanoparticles

To obtain the optimal 1:1 composition of FePt alloy nanomaterials by polyol synthesis, the iron precursor (iron pentacarbonyl, Fe(CO) 5 ) must be used in excess, because the Fe(CO) 5 exists in the vapor phase at the typical temperatures used for FePt synthesis and cannot be consumed completely. Fabrication of Fe 3 O 4 nanoparticles by consuming the excess iron precursor was an effective strategy to make full use of the iron precursor. In this paper, a facile post-treatment method was applied to consume the excess iron, which was oxidized to Fe 3 O 4 after post-treatment at 150 and 200 °C, and a monodisperse binary FePt-Fe 3 O 4 nanoparticle system was generated. The post-treatment method did not affect the crystal structure, grain size, or composition of the FePt nanoparticles. However, the content and grain size of the fcc-Fe 3 O 4 nanoparticles can be increased simply by increasing the post-treatment temperature from 150 to 200 °C.