Using Silica Shell to Improve the Surface of Magnetite Prepared by Biosynthesis Method

The combined of superparamagnetic properties (magnetite) and surface characteristics (silica), can produce structures with multiple capacities. The preparation of such magnetite-silica core-shell nanoparticles involves high costs in their execution and longer time. In this work, Fe 3 O 4 @SiO 2 CSNPs were synthesized in two stages to control their size and the possibility of adjusting their characteristics. First, Fe 3 O 4 NPs were synthesized by a green method using carob leaf extract, then coating the magnetite nanoparticles with a silica layer was done by using Tetraethylorthosilicate (TEOS) as a silica precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared, and vibrating sample magnetometer techniques were used to characterize the magnetite-silica CSNPs. TEM images confirms that Fe 3 O 4 NPS and Fe 3 O 4 @SiO 2 CSNPs synthesized had a spherical shape and were within 9 and 17 nm. The average crystallite sizes of the synthesized Fe 3 O 4 NPs and Fe 3 O 4 @SiO 2 CSNPs were found to be 17.8 nm and 20 nm. The VSM indicated that the magnetization decreased due to being coated with silica.