Low‐Temperature Synthesis of Phase‐Pure 0D–1D BaTiO 3 Nanostructures Using H 2 Ti 3 O 7 Templates

One‐dimensional (1D) barium titanate (BaTiO 3 ) nanowires, which were uniformly covered with 0D BaTiO 3 nanocrystals, were synthesized by using a simple solvothermal reaction of protonated trititanate (H 2 Ti 3 O 7 ) nanowires with barium hydroxide octahydrate [Ba(OH) 2 · 8H 2 O] at 80 °C in ethanol/water mixed solvent systems. The compositions of the mixed solvents ― the volume ratio of ethanol to deionized water ― was a key controlling parameter in order to determine the phase formation and primary particle size of the 0D BaTiO 3 nanocrystals. Single‐phase cubic perovskite BaTiO 3 started to form at 80 °C in a mixed solvent containing more than approximately 60 % by volume of ethanol. Field‐emission scanning electron microscopy (FESEM) and high‐resolution transmission electron microscopy (HRTEM) analysis revealed that the as‐prepared BaTiO 3 retained its wire‐shaped morphology with nanocrystals on the surface. Furthermore, the synthetic mechanism of the 0D‐1D BaTiO 3 nanostructures was demonstrated in view of the dielectric tuning of the mixed solvent and the similarities between the crystal structures of BaTiO 3 and H 2 Ti 3 O 7 .