Microwave Hydrothermal Synthesis and Characterization of ZnO Nanostructures in Aqueous Solution

ZnO nanostructures were prepared in aqueous solution by microwave hydrothermal synthesis. X- ray diffraction （XRD） and field emission scanning electron microscopy （FESEM） were used to characterize ZnO nanostructures （ZNs）. The effects of pH, reaction temperature and reaction time on yield of ZnO were investigated. The yield of ZnO increased significantly with the increase of pH value, reaction temperature and reaction time. High yield and well crystallinity of ZNs could be obtained at 120~C for 60min by microwave hydrothermal synthesis. The spherical and rugby-like ZNs were obtained at 120 ℃ without triethanolamine （TEA） and with TEA （mass ratio, r = mzn2＋ ： mTEA = 1 ： 1）, respectively. The concentration of Zn（OH）2- ions in the reaction solution and TEA had an important effect on the nucleation and morphology of ZnO nanostructures. Mechanism for the formation of ZnO nanostructures was proposed.