Surfactant-assisted hydrothermal synthesis of 3D urchin-like cobalt-nickel microstructures

Novel urchin-like CoNi alloy microstructures with diameter of 7.5 +/- 0.8 mu m were successfully prepared by a hydrothermal route at 120 degrees C for 10 h, in which cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecyl benzenesulfonate (SDBS) were used. The samples were characterized by XRD, SEM, TEM, and SQUID techniques. It was found that the ratio of surfactants (CTAB/SDBS) and reaction temperature have great effects on the size and shape of the final CoNi alloys. The magnetic measurements reveal that the urchin-like CoNi microstructures display ferromagnetic behavior with coercivities of 177.2 and 149.8 Oe at 2 and 300 K, respectively, which are higher than those of the bulk counterpart. These urchin-like CoNi alloy are expected to have significant potential applications in the fields of catalysis and magnetic storage. (C) 2015 Elsevier B.V. All rights reserved.