Self-Assembled 3D Flower-Like Hierarchical β-Ni(OH)2 Hollow Architectures and their In Situ Thermal Conversion to NiO

Three-dimensional (3D) flower-like hierarchical beta-Ni(OH)(2) hollow architectures were synthesized by a facile hydrothermal route. The as-obtained products were well characterized by XRD, SEM, TEM (HRTEM), SAED, and DSC-TGA. It was shown that the 3D flower-like hierarchical beta-Ni(OH)(2) hollow architectures with a diameter of several micrometers are assembled from nanosheets with a thickness of 10-20 nm and a width of 0.5-2.5 mu m. A rational mechanism of formation was proposed on the basis of a range of contrasting experiments. 3D flower-like hierarchical NiO hollow architectures with porous structure were obtained after thermal decomposition at appropriate temperatures. UV-Vis spectra reveal that the band gap of the as-synthesized NiO samples was about 3.57 eV, exhibiting obviously red shift compared with the bulk counterpart.