The Morphology Control of BaTiO3 Particles Synthesized in Water and a Water/Ethanol Solvent

The experimental conditions for the growth of shape-controlled BaTiO3 particles in NaOH and Ba(NO3)2 aqueous and water/ethanol solutions using various TiO2-containing precursors were studied at 80°C–100°C. The different chemistries and physical characteristics of the precursors resulted in different BaTiO3 formation rates and morphologies. Nanocrystalline anatase led to irregularly shaped BaTiO3 particles, whereas star-like, single-crystalline BaTiO3 particles grew from aerogel TiO2 and sodium titanate (NT) belts in alkaline aqueous solutions. With the addition of ethanol, the star-like BaTiO3 particles changed to square-like, the size of which decreased with an increase in the ethanol content. The electron microscopy observations supported a dissolution–precipitation mechanism as the primary reaction mechanism for the formation of BaTiO3 nanocrystals, which further aggregated into single-crystalline star- or square-like particles by oriented attachment. The modification in the water solution with ethanol is believed to influence both the nucleation and aggregation process and consequently influence the particle shape and size.