Synthesis of β-Co (OH)2 platelets by precipitation and hydrothermal methods

Abstract

Hexagonal β-Co (OH)2 platelets with high crystallinity (0.3-10 μm in average diameter and ∼5 in aspect ratio) have been synthesized. The platelets of 0.3-0.5 μm in diameter were prepared by a precipitation method, and their sizes were affected by the cobalt ion concentration in the suspensions. Adding rate of precipitant, stirring rate of solution, and aging temperature gave little effect on their morphologies. The platelets with well developed facets were synthesized with high reproducibility, when chloride salt was used as a Cosource and the suspension was aged at room temperature for 86.4 ks. The platelets have been enlarged up to 5-10 μm with maintaining morphology (hexagonal shape, ∼5 in aspect ratio) by hydrothermal treatment (at 393 K for 86.4 ks in 12 mol/dm3 NaOH aqueous solution).