Comparative study of perovskites obtained by using polymeric precursors with composition La_0,6Ca_0,4(Co, Mn)O₃ for use in combustion catalysis

Materials with the perovskite structure are potential catalysts to reduce emissions of pollutants components into the environment. In the synthesis of perovskites, several methods have been proposed. In this work, lanthanum manganate compositions and lanthanum cobaltate with partial substitution of calcium (La_0.6Ca_0.4MnO₃ and La_0.6Ca_0.4CoO₃, respectively), were synthesized using the polymeric precursor method. The powders obtained after 4h at 300° C (5° C/min), were calcined at temperatures of 700 and 900° C for 4 h (10° C/min), and characterized by X-ray Diffraction and Scanning Electron Microscopy. Comparing the X-ray Diffraction of the compositions manganate and lanthanum cobaltate, as the temperature increases, there is an increase in crystallinity, even more evident in manganate. TG curves showed similar thermal stabilities, with greater weight loss for the material cobaltate. The perovskites obtained were single phased, nanometric and had good porosity, making these potential catalysts appropriate properties for application in combustion reactions (author)