Controllable synthesis of single-crystalline Fe3O4 polyhedra possessing the active basal facets

In the present paper, we report on the controllable preparation of single-crystalline Fe3O4 microrhombic dodecahedra possessing the active basal facets in high yield through a facile hydrothermal route. The growth mechanism of the microcrystals is discussed. From a crystallographic point of view, the shapes of the crystals are determined by the ratio of the growth rate along < 100 > to < 111 > directions. The pH values of the precursor solution strongly affected the morphologies of the products. When pH value was adjusted to 8-10, well-defined Fe3O4 truncated microrhombic dodecahedra exposing the active basal Surfaces ({1101}) with narrow size-distribution (< 10%) were obtained. The sizes of the Fe3O4 truncated microrhombic dodecahedra are dependent upon the reaction time. The magnetic properties of the products are sensitive to the crystal size. The synthesized well-defined Fe3O4 microcrystals with active basal facets may have important applications in many fields.