Regularities in the synthesis of zinc oxide nanoparticles in an aqueous medium by laser ablation

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