Preparation and Properties of Magnetic Hematite Core/Alumina Shell Nanospheres

Abstract

Magnetic core/alumina shell (MFeCA) structured nanospheres were obtained from a hematite core/alumina precursor shell (HFeCAP) nanosphere precursor. A uniform alumina layer was coated on the surface of -Fe2O3 by the self-assembly of a stearic acid/alumina isopropoxide complex. Hematite cores of the nanospheres were then reduced under H2/N2 gas flow to produce the MFeCA nanospheres. Transmission electron microscopy images showed that the products possessed a distinct core-shell structure. N2 sorption measurements showed that the uniform accessible pore size was 5.2 nm. The surface area was 140m2/g and pore volume were 0.22 cm3/g. Saturation magnetization values indicated the product had a high degree of magnetization (50.2 emu/g).