Controllable synthesis and growth mechanism of α-Co(OH)2 nanorods and nanoplates by a facile solution-phase route

A facile chemical precipitation route has been developed to control synthesis of α-cobalt hydroxide nanostructures with rod-like and plate-like morphologies. The α-Co(OH)2 nanorods were achieved in large quantity when the experiments were carried out in the presence of a suitable shape-controlling reagent polyvinyl pyrrolidone (PVP), while the α-Co(OH)2 nanoplates were obtained when the experiments were conducted in the absence of PVP, whilst keeping other experimental conditions constant. The chemical composition and morphologies of the as-prepared α-Co(OH)2 nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of polymer PVP on the morphologies of α-Co(OH)2 nanoparticles were discussed in detail. The results indicated that PVP played a key role for the formation of α-Co(OH)2 nanorods. The growth mechanism of the as-synthesized nanorods and nanoplates were discussed in detail based on the experimental results. A possible growth mechanism has been proposed to illustrate the growth of α-Co(OH)2 nanorods. - Graphical abstract: A facile solution-phase route has been developed to synthesize α-Co(OH)2 nanorods and nanoplates. The possible growth mechanism of nanorods and nanoplates was proposed. Highlights: ► A facile controllable route was described for α-Co(OH)2 nanowires and nanoplates. ► The α-Co(OH)2 nanowires were achieved in the presence of shape controller PVP. ► The α-Co(OH)2 nanoplates were obtained in the absence of shape controller PVP. ► The shape controller PVP played a key role in the formation of α-Co(OH)2 nanowires.