Flower-like NiO nanoarchitectures, comprising self-assembled nanosheets, were prepared by heated Ni(OH)2 at 400 ℃, which were synthesized using Ni(NO3)2·4H2O and urea with ethanol and water as media under the condition of constant temperature of 85 ℃ by homogeneous precipitation. The structures and properties of powder have been studied by various techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, Fourier transform infrared(FTIR), BET (Brunauer-Emmett-Telle...