Nanodesigning of SiO2 powders obtained from silica sols by ultrasonic spray pyrolysis

摘要

The mechanism of the synthesis of silicon dioxide particles by ultrasonic spraying of a silica sol as a precursor is the subject of this work. The structural design of the obtained particles was defined as an organized structure of basic motives, silica chains forming so] particles, sub-particles and finally up to the particle level. TGA analysis was employed to define the size of the silica chains in the sol particles, The mean particle size obtained by spray pyrolysis was 1.68 mu m, with sub-particles of 25-30 nm. Based on the application of a suitable theoretical model, the mean particle diameter and sub-particle values were calculated as 1.8 mu m and 38.4 rim, respectively. The theoretically and experimentally obtained values are in good agreement, confirming that advanced modeling of the silicon dioxide structure at the particle and sub-particle level is possible. The mean size of a sol particle obtained in the hydrothermal procedure was 7.5 nm and the size of the structural motive of the silica chain consisting of sol particles is built up from 18-20 tetrahedral cells of silicon dioxide.