Characteristics and reducibility of nanosized La1-xCexCoO3 perovskites synthesized by reactive grinding

Abstract

Two (La,Ce)CoO₃ perovskite-type oxides prepared by reactive grinding have been characterized by means of X-ray diffraction, N₂ adsorption/desorption isotherms, SEM, H₂-TPR. Both samples show a nanocrystalline phase and rather high surface area. The thermal stability of cobalt ions in such solids has been studied under reducing conditions. H₂-TPR results indicate that the reduction of Co³⁺ to Co⁰ occurs in a multiple-step. The partial replacement of La³⁺ by Ce⁴⁺ has promoting effects on the reducibility of cobalt ions. A decreased reduction temperature of cobalt ions in the presence of Ce⁴⁺ leads to an increased dispersion of the reduced phase for La_0.9Ce_0.1CoO₃ perovskite precursor.

Keywords: perovskite; reduction; cobalt; La-Ce-Co; dispersion; metal.