Morphology of particles prepared by spray pyrolysis from organic precursor solution

To control the morphology of the particles prepared from high-concentration solution under severe preparation conditions, an organic polymeric precursor solution was introduced in spray pyrolysis. In the aqueous solution, hollow particles were formed by the surface precipitation because of rapid drying rate of droplet in the severe preparation condition. On the other hand, in the polymeric precursor solution, the polymeric chain formed from the esterification reaction between carboxyl and hydroxy groups of citric acid (CA) and ethylene glycol (EG) changed the drying characteristics of droplet. When a droplet was passing through the quartz reactor, a droplet turned into viscous gel precursors, which retarded the precipitation of salts inside droplet. Therefore, the particles prepared from polymeric precursor solution had a spherical shape and a filled morphology by the volume precipitation of salt.