Nanoparticle architectures templated by SiO2/Fe2O3 nanocomposites

Reverse microemulsion techniques combined with templating strategies have led to the synthesis of four types of nanoparticles. First, homogeneous SiO2-coated Fe2O3 (SiO2/Fe2O3) nanoparticles with controlled SiO2 shell thickness (1.8-30 nm) were synthesized by reverse microemulsion. These nanocomposite particles were used as templates for the deposition of a mesoporous silica shell. The iron oxide core in SiO2/Fe2O3 could be partially and completely etched to produce rattle-type SiO2/Fe2O3 nanoballs and hollow SiO2 nanoballs, respectively. These facile synthetic methods led to the formation of different nanoparticle architectures with tailored silica shell thickness and porosity.