One pot and sonically assisted synthesis of Fe3O4 and SiO2@Fe3O4

Magnetite (Fe3O4) and core-shell SiO2@Fe3O4 nanoparticles were successfully synthesized through a one pot assisted by sonication method. The products were morphologically, physically and chemically characterized using Transmission Electron Microscopy (TEM), N-2 adsorption-desorption, and Fourier Transform Infra-red (FTIR). In this research, concentration of tetraethyl orthosilicate (TEOS), a precursor of SiO2, was varied by 1, 3 and 5 mmol in order to control the SiO2 shell thickness. The FTIR measurements showed that the increasing of TEOS concentration was parallel with the increasing of Si-O stretching vibration peak intensity revealing an enlargement of SiO2 shell thickness. It was proved by morphological study where the addition of 1 mmol of TEOS has approximately 2 nm of shell thickness while by using 5 mmol was similar to 10 nm of shell thickness. Magnetite nanoparticle has 80.43 m(2) g(-1) of BET surface area but dramatically decreased to 55.74 m(2) g(-1) after incorporating of SiO2 (TEOS 5 mmol) caused by the presence of CTAB in pore channel.