Solid-State Synthesis of LaCoO3 Perovskite Nanocrystals

A solid‐state reaction process has been developed to synthesize perovskite‐type LaCoO3 nanocrystals with grain diameters of 15–40 nm. In the first step of the preparation, ∼5 nm composite hydroxide nanoparticles are synthesized by the solid‐state reaction of La(NO3)3·nH2O and Co(NO3)2·6H2O with KOH at ambient temperature. A perovskite‐type rhombohedral LaCoO3 phase appears at 550°C, after the hydroxide has been calcined at various temperatures. The phase transformation process is complete at ∼800°C, yielding a single‐phase binary oxide. The results indicate that the new process is convenient, inexpensive, and effective for obtaining LaCoO3 nanocrystals with high yield.