Pictures and explanations

Figure1:

Coin for size comparison.

Figure 2:

The manufacture of nanostructured titania particles made by titanium tetraisopropoxide oxidation in a premixed methane-oxygen aerosol reactor is precisely controlled with the electric field across the flame created by the two plate electrodes. The plates attract flame ions that attach onto the newly formed titania particles that repel each other freezing particle collisions and growth at the most decisive stage for particle growth in the flame. By selecting the electric field intensity, nanoparticles with precisely controlled aggregate and primary particle size and crystallinity can be made.

Figure 3:          

Nanostructured composite silica-carbon particles at high production rates (up to 700 g/h) are synthesized by oxidation of hexamethyldisiloxane in our pilot-scale air-hydrogen burner. The turbulent diffusion flame is up to 70 cm long and the product powder is collected in a commercial 2.5 m high baghouse filter, which is periodically cleaned by air-pressure shocks.

Figure4:

Aerosol diffusion flame reactor producing titania nanoparticles (left) and schematic of particle formation and growth in the flame (right). The precursor (here: titania tetra isopropoxide) is introduced as vapor into the methane-oxygen diffusion flame. Oxidation of the precursor gives product molecules which form clusters by nucleation. These small particles grow further by condensation, coagulation and coalescence. Single spherical  or aggregate product particles are obtained depending on concentration and temperature profiles as well as particle residence time in the flame.

Pictures courtesy of Professor Pratsinis