材料期刊网

Cobalt flowerlike architectures composed of hexagonal nano-platelets have been synthesized by a simple hydrothermal. reduction method. The architectures are fabricated by the reaction Of COCl2 with NaOH at 140-180 degrees C in the presence of sodium dodecyl benzenesulfonate (SDBS), with NaH2PO2 center dot H2O as reducing agent. The diameters of the flowers range from 8 to 10 mu m, and the average thickness of the hexagonal sheets is about 100 nm. Higher reaction temperatures and the proper concentration of sodium hydroxide (NaOH) are key requirements for the fabrication of the flowerlike architectures. A growth mechanism for these architectures is proposed on the basis of the characterization by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The magnetic hysteresis loops at 5 K and 295 K of the cobalt flowerlike architectures show ferromagnetic characteristics with coercivities of 371 Oe and 197 Oe, respectively. Our work may shed light on the designed fabrication of complex 3D architectures of other materials. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008.