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

Abstract

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)₃ · xH₂O + CoC₂O₄ · yH₂O, and a heteronuclear complex (La–Co–CN), La[Co(CN)₆] · 5H₂O. 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.