[Study on the preparation and spectral characteristics of nano-NiO]

The NiO nanoparticles with the size of 9-30 nm were prepared by solid state method using nickel acetate and sodium hydroxide as the raw materials, and Tween 80 as the dispersant. The structure, morphology, size, and infrared and UV-Vis spectra were characterized by XRD, TEM, FTIR and UV-Vis, respectively. The XRD and TEM revealed that the products are spherical with cubic structure. The infrared absorption band of the NiO nanoparticles (437 cm(-1)) red-shifts 47 cm(-1) compared with that of bulk NiO(484 cm(-1)). The UV-Vis optical absorption is related with the size of the particles. The bulk NiO has no absorption in the UV-Vis region, while the 10 nm NiO nanoparticles have stronger absorption observed at the wavelength about 309 nm, and the direct band gap energy is estimated to be about 4.2 eV which is obviously blue-shifted 0.55 eV compared to that of bulk NiO (3.65 eV). The surface effect and quantum size effect of the NiO nanoparticles indicated that the products will have potential application in the optical and electrical areas.