3D self-assembled polar . non-polar NiO nanoparticles nanoengineered from turbostratic Ni(OH)(NO) and ordered β-Ni(OH) intermediates.

A surfactant-free ammonia and carbamide precursor-modulated engineering of self-assembled flower-like 3D NiO nanostructures based on ordered β-Ni(OH) and turbostratic Ni(OH)(NO) nanoplate-structured intermediates is reported. By employing complementary structural and spectroscopic techniques, fundamental insights into structural and chemical transformations from intermediates to NiO nanoparticles (NPs) are provided. FTIR, Raman and DSC analyses show that the transformation of intermediates to NiO NPs involves subsequent loss of NO and OH species through a double-step phase transformation at 306 and 326 °C corresponding to the loss of free interlayer ions and HO species, respectively, followed by the loss of chemically bonded OH and NO ions.