On the Electrochemical Synthesis of Superparamagnetic Iron Oxide Nanoparticles with Low Coercivity Using a Magnetic Field

An improved electrochemical method for the synthesis of superparamagnetic iron oxide nanoparticles (NPs) with low coercivity is presented, which provides a high yield and good potential for scalability. The electrochemical synthesis method is optimized by changing parameters such as the composition of the electrolyte solution, the configuration of the electrodes, sonication during the synthesis process, and the use of a magnetic field for the selective sampling of magnetic NPs from the reaction zone. The obtained NPs are studied by X-ray diffraction analysis, transmission electron microscopy, X-ray absorption spectroscopy, and vibrational magnetometry. The X-ray diffraction patterns show that the synthesized magnetic NPs are dominated by the cubic phase, and according to X-ray absorption spectroscopy data, iron is in the oxidation state Fe³⁺. Taken together, these results indicate the formation of the γ-Fe₂O₃ phase. According to transmission electron microscopy and X-ray peak broadening data, the average particle size is 13 and 8.6 nm, respectively. Vibrational magnetometry measurements indicate a trend towards decreasing coercivity with decreasing particle size. The obtained magnetic NPs, due to their characteristics, can be applied in the field of biomedicine.