Precipitation of Uniform ZnO Particles with Controllable Layered Structure from Aqueous Solutions

Zinc nitrate precipitated with NaOH solution under double-jet conditions produced uniform nanostructured zinc oxide particles containing stacked nanoplates at 80 degrees C in the presence of starch sodium octenyl succinate (SSOS). In the absence of SSOS, nonuniform agglomerated ZnO particles and hexagonal nanorods were obtained. The presence of SSOS provided important hints on particle formation and confirmed that submicronic particles resulted from nanocrystals oriented aggregation. The formation kinetics of layered structures was followed by SEM observations, suggesting that they result from a rapid aggregation of about 40nm primary nanoparticles followed by rearrange into organized layered structures. Oxide materials with this shape are especially interesting for catalytic, piezoelectric and sensing applications. The stacked ZnO exhibits a surprisingly good activity for aqueous photocatalytic decompositions of 4-chlorophenol under visible light.