Comparison of the effect of reaction parameters on particle size in the formation of SiO2, TiO2, ZrO2 nanoparticles

Abstract

Monodisperse SiO2, TiO2, and ZrO2 nanoparticles were synthesized by hydrolysis of tetraethylorthosilicate (TEOS), tetraethylorthotitanate (TEOT), and zirconium normal propoxide (ZNP), respectively, in a semi-batch reactor, which consisted of a reservoir of starting solutions, a micro feed pump to supply the solutions, a water bath, and a reactor with a stirrer. The effects of three parameters (reaction time, R=(H2O/[TEOS or TEOT or ZNP], and feed rate of reactant) on particle size were observed. The main differences in the formation Of SiO2, TiO2, and ZrO2 nanoparticles were as follows. (1) Mean particle size Of SiO2 increased with increasing the reaction time, whereas the increase of reaction time decreased the particle size of TiO2 and ZrO2. (2) TiO2 and ZrO2 particles should be prepared at high water concentration to obtain the nanoparticles and SiO2 particles have to be synthesized at low water concentration by contraries. (3) In the case Of SiO2, increasing the feed rate of reactant decreased the particle size, while the particle size of TiO2 and ZrO2 increased with increasing the feed rate. (C) 2003 Elsevier Science B.V. All rights reserved.