Flame synthesis of silica nanoparticles by adopting two-fluid nozzle spray

Aggregation-free amorphous silica nanoparticles were synthesized from TEOS by flame pyrolysis with liquid-phase precursors fed by a two-fluid nozzle. The effects of key variables such as pressure of dispersion air, precursor feed rate, hydrogen flow rate, and precursor concentrations on the particle morphology and size were investigated by TEM and BET. The morphology of as-prepared silica nanoparticles was spherical, non-hollow and non-aggregated. The average particle diameters determined by BET analysis ranged from 9 to 68 nm and were proportional to the precursor feed rate, hydrogen flow rate, and precursor concentration. On the contrary, the average particle size was reversely proportional to the pressure of dispersion air.