Hydrothermally synthesized barium titanate nanostructures from K2Ti4O9 precursors: Morphology evolution and its growth mechanism

A morphology-controlled synthesis of barium titanate (BaTiO3) nanostructures from nano-whiskers to nanoparticles, were prepared via a hydrothermal strategy by manipulating the alkalinity and reaction temperature. Initially, the K2Ti4O9 precursors almost remain unchanged in the temperature of 80–160 °C at 0.1 M. By increasing the alkalinity and temperature, the BaTiO3 nanostructures initially undergoes ion exchange with precursors while retaining the morphology at the self-sacrifice of K2Ti4O9 nano-whiskers, followed by the formation of BaTiO3 nano-maces. Finally, recrystallization occurs and converts into nanoparticles at 120–220 °C at 0.8 M. Also, time-dependent experiment was conducted to probe the ion exchange process. The formation mechanism involves the generation of chemical site inducing the ion exchange process and the dissolution–precipitation reaction. By investigating the synthesis and morphology evolution of one-dimensional BaTiO3 nanostructures, this work may be of great significance for fabrication of other perovskite-type MTiO3 (M = Ca, Sr, Pb).