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Perovskite Oxide LaCoO3 Prepared by Solid-state Reaction, Pyrolysis of a Co-Precipitated Precursor or Pyrolysis of a Heteronuclear Complex

Susumu NAKAYAMA*, Tadashi TERADA†, Shinichi KAKITA††, Shinji IMAI††† and Masatomi SAKAMOTO*,††††

Department of Applied Chemistry and Biotechnology, Niihama National College of Technology; 7-1, Yagumo-cho, Niihama-shi 792-8580 Japan
† New Tecks Co., Ltd.; 1-5-20, Nankohigashi, Suminoe-ku, Osaka-shi 559-0031 Japan
†† Daiichi Kigenso Kagaku Kogyo Co., Ltd.; 4-4-14, Koraibashi, Chuo-ku, Osaka-shi 541-0043 Japan
††† Sharp Takaya Electronics Industry Co., Ltd.; 3121-1, Satomi, Satosho-cho, Asakuchi-gun, Okayama 719-0301 Japan
†††† Department of Material and Biological Chemistry, Faculty of Science, Yamagata University; 1-4-12, Kojirakawa-machi, Yamagata-shi 990-8560 Japan

The perovskite oxide LaCoO3 was synthesized by three different preparative methods i.e., the calcination of a mixture of La2O3 and CoO (La-Co-O) and pyrolysis of a co-precipitated precursor (La-Co-ox), La2(C2O4)3ExH2O+CoC2O4EyH2O, and a heteronuclear complex (La-Co-CN), La[Co(CN)6]E5H2O. The obtained powders were characterized by thermogravimetric analysis, infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and specific surface area measurements. The formation of LaCoO3 single phase is clearly recognized for La-Co-O, La-Co-ox and La-Co-CN at temperatures above 1000, 1200 and 600 °C, respectively. The nano-sized LaCoO3 powder was obtained at low temperatures by pyrolysis of La-Co-CN. The mean particle diameter of La-Co-CN calcined at 600 °C for 2 h was 72 nm.


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