Synthèse et propriétés physiques d'oxyde mixtes à base de lanthane calcium et aluminium

Abstract

La1–xCax Al O3 (0 ≤ x ≤ 0.6) perovskite-type oxides were prepared by coprecipitation method using metal nitrate salts as cation precursors and NaOH solution as the precipitating agent. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) results indicate that decomposition of the precursor to the oxide begins at ~ 800°C. Powder X-ray diffraction (XRD) patterns confirm the formation of the perovskite phase. Show two IR analysis active vibrational modes at 450 and 670 cm−1 which are assigned to AlO6 octahedra of the oxide matrix. The microstructure and morphology of the compounds show that the particles are nearly spherical in shape and are agglomerated. The electrochemical study by cyclic voltammetry and chronoamerometry shows that the richest sample in calcium has the best catalytic activity for the evolution of oxygen and the oxidation of methanol.