Preparation and Properties of Magnetic Hematite Core/Alumina Shell Nanospheres

Abstract

Magnetic core/alumina shell (MFeCA) structured nanospheres were obtained by a hematite core/alumina precursor shell (HFeCAP) nanosphere precursor. A uniform alumina layer was coated on the surface of α-Fe2O3 by the self-assembly of a stearic acid/alumina isopropoxide complex. Hematite cores of the nanospheres were then reduced under H 2 /N 2 gas flow to produce the MFeCA nanospheres. Transmission electron microscopy images showed that the products possessed a distinct core-shell structure. N 2 sorption measurements showed that the uniform accessible pore size was 4.0 nm. The surface area was 140m 2 /g and pore volume was 0.22 cm 3 /g. Saturation magnetization values indicated the product had a high degree of magnetization (50.2 emu/g).