Synthesis of magnetic core-shell structure Fe3O4@MCM-41 nanoparticle by vesicles in aqueous solutions☆

In this study, magnetic core-shell structure Fe₃O₄@MCM-41 nanoparticles were synthesized with vesicles as soft templates. In the preparation, FeCl₂ and tetraethy orthosilicate (TEOS) were selected as Fe processor and Si precursor, respectively. Stable vesicles first formed in 0.03 mol·L^-1 1:2 mixture of anionic surfactant sodium dodecyl sulfate and cationic surfactant cetyltrimethyl ammonium bromide. Then, TEOS was added in the vesicle aqueous solution, leading to a highly dispersed solution. After high-temperature calcination, Fe₃O₄@MCM-41 nanoparticles were obtained. Their structure and morphology were characterized by Saturn Digisizer, transmission electron microscope and vibrating samplemagneto-meter. The results indicate that the vesicles are spherical and their size could be tuned between 20 and 50 nm. The average grain diameter of synthesize magnetic core-shell Fe₃O₄@MCM-41 particles is 100-150 nm and most of the mare in elliptical shape. The dispersion of magnetic particles is very good and magnetization values are up to 33.44 emu·g^-1, which are superior to that of other Fe₃O₄ materials reported.