One-step silica coating of cetyltrimethyl ammonium bromide-stabilized alpha-Fe2O3

The alpha-Fe2O3 nanoparticles were coated with silica using intermediated surfactant such as cetyltrimethyl ammonium bromide (CTAB). After the formation of a thin intermediate layer in basic solution without any purification, TEOS was added directly to the solution for further silica growing. Silica thickness can be controlled through the various synthetic conditions (5 to 50 nm). The synthesized powder was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and UV-visible spectroscopy. XRD and UV-visible spectroscopy of silica coated alpha-Fe2O3 is preserved constant after coating silica, suggesting that the SiO2 layers can be regarded as protecting layers without destroying the properties of the alpha-Fe2O3 nanoparticles.