Effect of Surfactant Concentration on Size and Morphology of Sonoelectrooxidized Fe3O4 Nanoparticles

Fe3O4 nanoparticles were successfully synthesized using electrooxidation of iron by a chronoamperometric technique in the presence of tetramethylammoniumchloride surfactant in an aqueous medium. The effect of surfactant concentration and ultrasonic excitation on the structural properties of the nanoparticles we studied using XRD, AES, FT-IR, TEM, and UV-visible spectroscopy. XRD results clearly showed the formation of the spinel phase of Fe3O4. The purity of the nanoparticles was confirmed by AES. FT-IR spectroscopy results confirmed that the surface of the Fe3O4 nanoparticles was covered by surfactant molecules due to electrostatic attraction. The resultant TEM images showed that the particle size and their size dispersion can be controlled by surfactant concentration and ultrasonic treatment. According to these images, an increase in surfactant concentration leads to a reduction in the particle size, a narrower size distribution, and also the particle shape changing from cubic, tetragonal, hexagonal, and triangular to quasi-spherical. Electron diffraction results show that the particles have polycrystalline structure. UV-vis spectroscopy, indicating that their maximum absorption wavelength and peak width decrease with increasing surfactant concentration and ultrasonic treatment.