Size-controlled synthesis of Fe3O4 magnetite nanoparticles on the exterior of talc layers

Abstract

The purpose of this study was to investigate the effect of OH concen- tration on the size of Fe3O4 nanoparticles (Fe3O4-NPs). Fe3O4-NPs with different cubic nanocrystal structure and percentage Fe3O4 content were successfully pre- pared, by use of the chemical co-precipitation method, on the exterior surface of talc, as solid substrate, by an environmentally friendly process. Ferric chloride, ferrous chloride, and sodium hydroxide were used as iron oxide precursors and reducing agent. The results showed that the morphology of the Fe3O4-NPs can be adjusted by changing the reaction conditions, for example volume of reducing agent and concentration of iron salts. Different size, dispersal, and the magnetic properties were obtained by changing the concentration of iron salts and NaOH. The products were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. The reaction was conducted in a non- oxidizing, oxygen-free environment. Because the interlamellar spacing of the talc was almost unchanged (ds = 0.94-0.87 nm), the Fe3O4-NPs were formed on the exterior surface of the talc. The average diameter of the Fe3O4-NCs could be varied from 6.62-8.13 nm in adjusting the concentration of NaOH. The size of the nanoparticles decreased as the amount of reducing agent was increased. These talc- Fe3O4 nanocomposites (talc-Fe3O4-NCs) may have potential applications in the chemical and biological industries.