Novel three-dimensional Co3O4 dendritic superstructures: hydrothermal synthesis, formation mechanism and magnetic properties

Abstract

Well-defined porous Co3O4 nanodendrites have been synthesized by a simple one-pot hydrothermal method combined with subsequent calcination. Importantly, after thermal treatment, the dendritic morphology could be completely preserved. The as-obtained superstructures are characterized by several techniques, such as powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy, elemental analysis, transmission electron microscopy, high-resolution TEM and magnetometry. On the dendritic hierarchical structures, a number of nanorods with different lengths and widths are connected to the main trunk with a diameter of about 50 nm and length of several micrometers. Each branch is about 0.5–1.0 μm with a width ranging from 100 to 400 nm. The possible formation mechanism was proposed on the basis of the contrasting experiments. It demonstrated that trisodium citrate and acetone play important roles in the synthesis of Co3O4 nanodendrites, while the other reaction parameters, such as reaction temperature, concentration of trisodium citrate and reaction time, have close relationships with the final morphology of the Co3O4 products. Optical properties of Co3O4 nanodendrites were characterized by Raman and UV-vis spectroscopy. Magnetic property measurement shows that Co3O4 nanodendrites have a low Neel transition temperature of 35 K. The as-prepared mesoporous Co3O4 nanostructures are expected to have great applications in many fields.