Effect of the intra-perovskite lattice copper on the reducibility of La(Co,Cu)O3.

Abstract

Nanocrystalline La(Co,Cu)O₃ perovskites have been characterized by several techniques including N₂ absorption/desorption, X-ray diffraction, Temperature-Programmed Reduction (H₂-TPR), Temperature-Programmed Oxidation (O₂-TPO). H₂-TPR and O₂-TPO results indicate that the reducibility of Co³⁺ in the ground La(Co,Cu)O₃ perovskites was promoted by the presence of the intra- lattice copper. An increased copper content leads to a decreased reduction temperature of Co³⁺ to Co⁰ and an increased dispersion of metallic copper-cobalt phase. The XRD and H₂-TPR studies also revealed that the perovskite structure of La(Co,Cu)O₃ is somewhat less stable than the-ones of LaCoO₃.