Multishelled Co3O4-Fe3O4 hollow spheres with even magnetic phase distribution: Synthesis, magnetic properties and their application in water treatment

Nowadays, despite the success evidenced in synthesis of hybrid materials, spherical hybrid materials are usually based on core-shell structures or alloy-like ensembles with homogenous distribution of all components. For core-shells, the performance of a core part is usually hampered due to a thick shell, and alloy-like ensembles commonly have low surface area. Therefore, the synthesis of hybrid multishelled hollow materials with both even phase distribution and well-ordered building blocks, may be a better choice. In this paper, we developed a new method to successfully fabricate Co3O4-Fe3O4 materials with the above ideal structure. As-prepared Co3O4-Fe3O4 products have definite structural advantages. Therefore, these Co3O4-Fe3O4 products not only exhibit excellent ability in waste-water treatment applications, but are also feasible for the fast recyclable treatment via a simple magnetic separation. In addition, they also show interesting structure-dependent magnetic properties and could serve as a model material for a heterogeneous antiferromagnet/ferromagnet system without clear/sharp interfaces. Needless to say, our newly developed synthetic approach may be extended toward the synthesis of other hybrid materials with even functional phase distribution.