One-step synthesis of nanocrystalline ZnO via cryomilling

In this work, the ZnO spherical nanoparticles with a diameter in the range of 10–30 nm have been prepared via mechanochemical oxidation of metallic Zn powders treated in a vibratory ball mill in the presence of air and liquid nitrogen. The as-prepared nanocrystals were characterized by XRD, HR-TEM, FTIR, XPS, and UV–vis spectroscopy. The results show that metallic zinc powder is completely converted to nanocrystalline ZnO within 48 h of cryomilling. The XPS analysis confirms the presence of incorporated nitrogen as well as Zn(OH)2 and carbonate species formed on the reactive structurally-disordered surface shell of the as-prepared nanoparticles. Compared with the pure ZnO, the light absorption by the as-prepared ZnO nanocrystals was shifted to longer wavelengths.