Hydrothermal synthesis of ultra fine β-Co(OH)2 nanowires with novel morphologies using supercritical water

Different morphologies of single-crystalline β-cobalt hydroxide (β-Co(OH)2) nanostructures are successfully synthesized in large quantities by a facile hydrothermal synthetic method with cobalt powder as the cobalt source, supercritical water and triethylamine as both an alkaline and a complexing reagent. This synthetic method has good prospects for the future large-scale production of single-crystalline β-Co(OH)2 nanostructures owing to its high yield, low cost, and simple reaction apparatus. Ultra fine nanowires, nanowires with branched ultra fine nanoneedle (forest) and nanobelt with branched nanoneedles (pan trees) like structures of cobalt hydroxide are obtained with varying the ratio between supercritical water and triethylamine by 1:0, 2:1 and 1:2, respectively. The obtained morphologies are hexagonal phase of β-cobalt hydroxide with high crystallinity.