Synthesis, microstructures and UV–vis absorption properties of β-Ni(OH)2 nanoplates and NiO nanostructures

Single-crystalline β-Ni(OH)2 nanoplates of hexagonal structure have been synthesized through a hydrothermal process. The β-Ni(OH)2 nanoplates possess well-defined hexagonal shapes with landscape dimension of 45–140 nm and thickness of 20–50 nm. The in-plane surfaces of hexagonal-shaped nanoplates lies on (0 0 1), and the side surfaces are (1 0 0), (01¯0) and (1¯10). Post-thermal decomposition of the β-Ni(OH)2 nanoplates led to the formation of single-crystalline NiO nanostructures with landscape dimension of 25–120 nm including nanorolls, nanotroughs and nanoplates. The sizes of the central hole in NiO nanorolls and the low-lying ground in NiO nanotroughs are in the range of 10–24 nm. The optical absorption bands in the wavelength range of 350–800 nm have been interpreted according to the ligand field theory.