The Regularities of the Synthesis of Zinc Oxide Nanoparticles in an Aqueous Medium by Laser Ablation

The mechanism of transition of colloidal nanoparticles of metallic zinc obtained by pulsed laser ablation (PLA) of a metal target in liquid with different pH into zinc oxide directly during PLA and their storage has been considered. It is shown that the rate of oxidation of metallic zinc particles in solution depends on the rate of two partial electrochemical reactions interconnected by the electron balance, namely, the rate of formation of the ionized form of zinc and the ionization discharge of oxygen dissolved in water. It has been revealed that the rate of oxygen delivery through the Prandtl boundary layer is the limiting stage of the zinc oxide phase formation process. As well, a number of powder samples are obtained using the PLA of metallic zinc in weakly acidic, neutral, and alkaline aqueous media and drying of the resulting colloidal solutions; their composition has been analyzed. According to X-ray phase analysis, exposure to atmospheric oxygen leads to significant further oxidation of the obtained powders; however, a metallic phase was detected in the sample after PLA in an alkaline medium. Thus, varying the conditions of the PLA provides wide opportunities for obtaining a final product with a specific composition and properties.