Synthesis and Characterization of Hollow Magnetic Alloy (GdNi 2 , Co 5 Gd) Nanospheres Coated with Gd 2 O 3

Uniform magnetic hollow nanospheres (GdNi 2 , Co 5 Gd) coated with Gd 2 O 3 have been successfully prepared on a large scale via a urea‐based homogeneous precipitation method using silica (SiO 2 ) spheres as sacrificed templates, followed by subsequent heat treatment. Nitrogen sorption measurements and scanning electron microscope reveal that these hollow‐structured magnetic nanospheres have the mesoporous shells that are composed of a large amount of uniform nanoparticles. After reduction treatment, these nanoparticles exhibit superparamagnetism that might have potential applications in medicine. Furthermore, the developed synthesis route may provide an important guidance for the preparation of other multifunctional hollow spherical materials.