Bulk synthesis of ZnO nanoparticles by the one-step electromagnetic levitational gas condensation method

The ZnO nanoparticles were synthesized by the one-step electromagnetic levitational gas condensation method with a relatively high production rate. In this method, the vapors ascending from a high temperature levitated Zn droplet were condensed and oxidized by He–0.2Ar and O2 gas mixtures, respectively, under both atmospheric and reduced pressures. Effects of carrier gas type and temperature, oxygen content, and reactor pressure on the size, size distribution and morphology of the particles were investigated. The particles were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy methods. The production rate of the crystalline ZnO nanoparticles was estimated as high as 300 g h−1. The results showed that decreasing the gas temperature and reactor pressure resulted in a smaller particle size and a higher fraction of rod-like nanoparticles.