Synthesis of perovskite-type (La1−xCax)CoO3 at low temperature using ethylene glycol and citric acid
2006
Taguchi, Hideki | Yamasaki, Satoshi | Nagao, Mahiko | Sato, Yumi | Hirota, Ken | Yamaguchi, Osamu
To synthesize perovskite-type (La₁₋ₓCaₓ)CoO₃ with good crystallinity (regularity of ions), a gel was prepared by adding ethylene glycol and citric acid to an aqueous solution of La(NO₃)₃ · 6H₂O, CaCO₃, and Co(CH₃COO)₂ · 4H₂O. Perovskite-type (La₁₋ₓCaₓ)CoO₃ (0.0 ≤ x ≤ 0.3) was obtained by firing the gel above 600 °C in air for 3 h. Samples were examined for oxygen content, crystallite size, specific surface area, and the catalytic activity of CH₄ oxidation. The samples were also investigated by transmission electron microscopy (TEM). Based on the variation in crystallite size and in the average particle size, the (La₁₋ₓCaₓ)CoO₃ particle became finer as x increased. In all samples, CH₄ oxidation occurred above 300°C. The catalytic activity of (La₁₋ₓCaₓ)CoO₃ fired at 700 °C monotonously increased as x increased.
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