Synthesis of Oxide Particles Using a Polymer-Assisted Spray Pyrolysis Reactor, and a Percolation Explanation of Particle Separation

Abstract

A vertical spray pyrolysis reactor was designed to produce separated/softly agglomerated oxide nanoparticles by dissolving a large amount of high molecular weight polymer into solutions of nitrous or acetic metals. The polymer played a role as a matrix that prevented the tendency of as-grown nuclei to make contacts inside the "polymer ball." Decomposition of the "polymer ball" at the end stage of the reactor released separated nanoparticles. On the first attempt, we produced particles of zinc oxide and compound oxide of CuO/ZnO/Al2O3 at different parameters of synthesis. We found that the size of the particles decreased, as a fraction of the polymer, as the mass increased. We used a percolation theory to explain the particle separation mechanism inside the "polymer ball." Separated nanoparticles were obtained if the volume fraction of the particles was far below the percolation threshold.