Synthesis and characterization of TiO2 powders by the double-nozzle electrospray pyrolysis method. Part 1. Refinement and monodispersion of sprayed droplets

By using the droplet-fixation method, quantitative analyses of the size and dispersion state of electrosprayed droplets were conducted. At first, titanium(IV) bis (ammonium lactate) dihydroxide (TALH) aqueous solution (2 wt%), as a precursor of TiO₂, was electrosprayed using single-nozzle setting, and the electrospray parameters were optimized. Fine and monodispersed droplets (5.00 μm with the geometrical standard deviation of 1.16) were successfully obtained. Then, applying the single-nozzle conditions, we tried to prepare the double-nozzle electrospray, where positively and negatively charged sprays were superimposed to neutralize the charges of droplets. As for the double-nozzle electrospray, relatively fine and monodispersed droplets (7.58 μm with the geometrical standard deviation of 1.37) were obtained. By using the double-nozzle electrospray, the final TiO₂ powder yield after pyrolysis can be much improved.