High-yield synthesis of dendritic Ni nanostructures by hydrothermal reduction

Uniform Ni dendritic nanostructures were prepared via a facile hydrothermal reduction approach in the presence of surfactants with a high yield of 98%. The morphology and structure of the products are characterized by scanning electronic microscopy (SEM), energy dispersive X-ray (EDX), transmission electronic microscopy (TEM), electron diffraction (ED) and X-ray diffraction (XRD) techniques. The assembled nanostructures were composed of ordered nanoscale fractal structure with the length of the dendrite trunks of 0.5-2 mu m, and the thickness of the dendrites of 10-30 nm, as characterized by SEM and TEM. The parameters that were essential for the special dendrite formation were studied by varying the hydrothermal temperature, the concentration of NaOH and the initial Ni2+ ions or CTAB, keeping other conditions unchanged. These materials exhibited ferromagnetic characteristics with an enhanced magnetic coercivity in comparison with the bulk nickel crystals and hollow Ni nanometer-sized spheres, which is attributed to their peculiar morphology. (c) 2007 Elsevier B.V. All rights reserved.