Hydrothermal synthesis of BaTiO ₃ nanopowders using TiO ₂ nanoparticles

Anatase TiO₂ nanoparticles, obtained by hydrolyzing titanium isopropoxide in distilled water, were used to synthesize BaTiO₃ (BT) nanopowder by the hydrothermal method. When titanium isopropoxide was used, BT nanopowder with a low tetragonality of 1.0070 was formed because of the presence of OH^- ions in the oxygen sites and Ba vacancies. However, by changing the titanium source from titanium isopropoxide to TiO₂ nanoparticles, a homogeneous BT nanopowder with similar particle size and a high tetragonality of 1.0081 was synthesized. The size of the BT nanopowder particles was decreased by reducing the synthesis time. In particular, the BT nanopowder that was synthesized at 220°C for 16 h with a Ba/Ti molar ratio of 4.0 exhibited a high tetragonality of 1.0083 and a small particle size of 126.0 nm.