2013 年 21 巻 p. 48-53
Synthesis of barium zirconate (BaZrO3) nanocubes with perovskite structure was carried out by the composite-hydroxide-mediated (CHM) approach. The synthesis was conducted using zirconium dioxide (ZrO2) as a zirconium-source starting material and barium hydroxide[Ba(OH)2] as a barium-source starting material. Through the use of these starting materials, BaZrO3 was prepared with a mixture of anhydrous sodium hydroxide (NaOH) and potassium hydroxide (KOH) as the reaction medium at 170~230℃ for 0~72h. Measurement by X-ray diffraction (XRD) confirmed the presence of perovskite BaZrO3 and indicated that the lattice of the obtained BaZrO3 was cubic. The amount of BaZrO3 increased as the reaction temperature increased. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation revealed BaZrO3 nanocubes. The results showed that BaZrO3 nanocubes could be shaped from ZrO2 and Ba(OH)2. In order to clarify the formation mechanism of the BaZrO3 nanocubes, various reaction conditions such as the processes of increasing, maintaining, and decreasing the temperature were investigated. BaZrO3 nanocubes with sharp-edged corners were formed via the CHM approach when the temperature was maintained at 230℃ for increasing periods of time.