Synthesis of Perovskite Oxide Nanocubes

Abstract

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.