Hydrothermal Synthesis of Hierarchical Nanocolumns of Cobalt Hydroxide and Cobalt Oxide

摘要

In this paper, we report a facile method to prepare high-yield one dimensional hierarchical β-Co(OH)2 nanocolumns through one-step hydrothermal synthesis with hydrazine hydrate and Na3PO4 as morphology-directing agents, which play important roles in the formation of hierarchical nanocolumn morphology. The hierarchical Co3O4 nanocolumns are obtained by the β-Co(OH)2 nanocolumns annealed at 400 °C for 4 h. The formation mechanism of hierarchical nanocolumns has been clearly demonstrated by studying morphology evolution processes of β-Co(OH)2 nanocrystals upon reaction time, which undergo two steps, the formation of nanorods and then growing sideways in the form of thin nanoplatelets to form hierarchical nanocolumns. Moreover the UV—vis spectra and magnetic properties of Co3O4 nanocolumns also have been investigated.