Evaluation of Na₂TiO₃ formation for producing crystalline BaTiO₃ nanoparticles by liquid–solid–solution process at low temperature

Crystalline barium titanate (BaTiO₃) nanoparticles were synthesized by refluxing in an air atmosphere at a low temperature using sodium hydroxide. The reaction mechanism of BaTiO₃ nanoparticle formation by this new liquid–solid–solution (LSS) synthesis route with refluxing in an air atmosphere at a low temperature of 80 °C was demonstrated to be a facile fabrication process for BaTiO₃ nanoparticles with a high crystalline quality and minimized agglomeration rate. BaTiO₃ nanoparticles were formed via sodium titanate (Na₂TiO₃), and the size of the BaTiO₃ nanoparticles decreased with increasing sodium hydroxide concentration. The formation of a Na₂TiO₃ intermediate phase was confirmed by energy dispersive X-ray spectroscopy and X-ray diffraction analysis. The capping ligands of BaTiO₃ suggest that hydroxyl and oleic acid are present. The dielectric constant of the crystalline BaTiO₃ nanoparticles was higher than 150.