Novel monopolar arrangement of multiple iron electrodes for the large-scale production of magnetite nanoparticles for electrochemical reactors

High-purity magnetite nanoparticles with a mixed quasi-spherical and cubic morphology have been successfully synthesized using a new alternating monopolar arrangement of multiple iron electrodes in water. The magnetite nanoparticles have a narrow size distribution with a mean size ranging from 20 to 30 nm, depending on the applied voltage and pH. The formation of magnetite nanoparticles is favored only in the pH range of 7–10; outside this range, magnetite nanoparticles cannot be produced. The magnetite nanoparticles exhibit ferromagnetic properties with saturation magnetization ranging from 16 to 75 emu/g. They demonstrated to be a promising electrocatalyst for oxygen reduction reactions in basic media. This facile method is a promising production route for magnetite nanoparticles and can be easily scaled up for large production.