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.

Graphical abstractNanocrystalline ZnO consisting of an ordered core surrounded by a disordered surface shell region has been synthesized via cryomilling of metallic Zn in presence of air and liquid nitrogen. The presence of incorporated nitrogen as well as hydroxyl and carbonate species formed on the reactive structurally-disordered surface shell of the as-prepared nanoparticles has been confirmed.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The nanocrystalline ZnO has been synthesized via cryomilling of metallic Zn. ► The size of as-prepared nanoparticles is about 15 nm. ► The XPS analysis confirms the presence of Zn in 2+ state. ►The light absorption by the as-prepared ZnO is shifted to longer wavelenghts.