Study on reaction mechanism of low temperature preparation of nanocrystalline LaCoO3-λ

Perovskite-type oxide nanocrystalline LaCoO3-λ was prepared using the citrate method. The structure and morphology of the samples were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The intermediate products were analyzed by thermal gravimetric and differential thermal analysis (TG-DTA) technology. The results showed that nanocrystalline LaCoO3-λ with a granula of 30–50 nm had a cubic perovskite structure. The reaction mechanism of low temperature preparation was suggested as follows: the metal complex was first formed by the combination of metal ion and citric acid; and then it decomposed into an aconitic acid complex, followed by an oxycarbonate, and finally a perovskite-type oxide.