Quench-Ring Assisted Flame Synthesis of SiO₂-TiO₂ Nanostructured Composite

Abstract

A flame aerosol reactor (FLAR) was used to synthesize SiO 2 -based nanocomposite materials of SiO 2 -TiO 2 in different precursor molar ratios and quench ring positions. Processing conditions were determined that resulted in formation of different crystal phases at different precursor concentration molar ratios. The results showed that the addition of SiO 2 inhibited TiO 2 phase transformation from anatase to rutile. The different morphology of SiO 2 -TiO 2 nanocomposite was primarily the result of changing the quench ring position. Quenching can stop the growth kinetics, and this was obtained by locating the quench ring at different positions in the particle formation process. At a lower position, a binary mixture of SiO 2 -TiO 2 was obtained in a core–shell structure. The difference in residence time for sintering and coalescence yielded different morphologies of SiO 2 -TiO 2 nanocomposites. The results from FTIR confirmed Si-O-Ti bonding for all samples. The samples of SiO 2 -TiO 2 exhibited better suspension in liquid than pure TiO 2 as confirmed by zeta potential measurements.