A Facile Hydrothermal Route to Flower‐Like Cobalt Hydroxide and Oxide

Flower‐like cobalt hydroxide [β‐Co(OH)2] consisting of nanosheet networks has been synthesized by a hydrothermal method from Co(CH3COO)2·4H2O in mixtures of water and glycerol/ethylene glycol at 200 °C. The morphology and phase of the cobalt hydroxide can be controlled by adjusting the experimental parameters that include cobalt acetate concentration and the volume ratio of water to glycerol/ethylene glycol. The possible formation mechanism of flower‐like cobalt hydroxide is discussed on the basis of experimental results. Cobalt oxide (Co3O4) flowers have also been obtained by thermal decomposition of cobalt hydroxide flowers in air at 400 °C. The products were characterized by powder XRD, TEM, selected‐area electron diffraction (SAED), high resolution TEM (HRTEM), and field‐emission SEM (FESEM). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)