Synthesis and Characterization of Novel Three-Dimensional Metallic Co Dendritic Superstructures by a Simple Hydrothermal Reduction Route

Abstract

Novel three-dimensional (3D) Co dendritic superstructures with an average diameter of ca. 15 µm were successfully prepared by a simple hydrothermal reduction route. The as-obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. It was shown that the 3D Co superstructures were comprised of dozens of well-aligned metallic Co dendrites with hierarchical assemblies radiating from the center. On the dendritic hierarchical structures, several leaves with different lengths and widths are connected to the main branch. The length of the main branch is several micrometers, and that of each leaf is about 0.5–1.5 µm with a width of 100−600 nm. A rational formation mechanism was proposed on the basis of the contrasting experiment. Compared with bulk cobalt, the 3D Co superstructures exhibited a decreased saturation magnetization (Ms) but an enhanced coercivity (Hc) due to their peculiar morphology.