Nanostructured particles by controlled precipitation techniques

Controllable synthesis of porous nickel–cobalt oxide nanosheets for supercapacitors

“…In our case, an excess amount of NH 4 NO 3 makes the bivalent Co 2+ 3 which will result in a relatively constant ratio of Co 2+ and Ni 2+ ions in solution. 35,36 Moreover, the Co 2+ and Ni 2+ ions have similar coordinated environment (similar coordinated number) and ion radius, and hence their diffusion rate in the electrolyte is similar. Additionally, Co 2+ and Ni 2+ ions also have similar affinity towards OH À ions according to their solubility constants (5.92 Â 10 À15 for Co(OH) 2 and 5.48 Â 10 À16 for Ni(OH) 2 ).…”

Evolution of cobalt hydroxide from 2D microplatelets to a 3D hierarchical structure mediated by precursor concentration

“…Precipitation of metal salt aqueous solutions by a base usually leads to the formation of homogeneous nanoparticles or even sub-micronic hydroxide particles when saturation occurs and hence the reactivity of the system can be well-controlled. 18 It is of great significance to develop a facile method to controllably fabricate the Co(OH) 2 structure with different morphologies, although it is challenging. The synthesis of 2-dimensional (2D) hexagonal Co(OH) 2 platelets was reported elsewhere.…”

Hydrothermal Synthesis of Hierarchical Nanocolumns of Cobalt Hydroxide and Cobalt Oxide

“…Co 3 O 4 nanorods or nanotubes were fabricated through thermal conversion of rodlike precursor, as well as β-Co(OH) 2 nanorod . Athough there are some reports about hierarchical structure of both β-Co(OH) 2 and Co 3 O 4 , such as flowerlike structure and hierarchical spheres . However, there is no report about one-dimensional (1D) hierarchical structure of both β-Co(OH) 2 and Co 3 O 4 by using hydrazine hydrate as the morphology-directing agent in the synthesis of β-Co(OH) 2 and Co 3 O 4 .…”