Perovskitas La1-xCaxMnO3 como catalizadores para oxidación total de compuestos orgánicos volátiles

STEGE, WALTER P.; CADUS, LUIS E.; BARBERO BIBIANA P.

Viña del Mar

Congreso; XXII Congreso Iberoamericano de Catálisis; 2010

La1-xCaxMnO3 perovskites were prepared by the citrate method and characterized by means of X-ray diffraction, thermal programmed desorption of oxygen, thermal programmed reduction, and measurement of specific surface area. The characterization results indicated that pure perovskite phases were obtained and their specific surface areas are appropriate for the application in catalytic oxidation. The unsubstituted perovskite, LaMnO3, could present a certain amount of Mn4+ and cationic vacancies, which is generally called oxidative non stoichiometry. The electronic unbalance yield by the partial substitution of lanthanum for calcium, a cation of lower oxidation state, caused an oxidation state increase of part of the manganese that occupy the B sites of the structure. Simultaneally, the amount of cationic vacancies decreased with the increase of the calcium amount. The catalytic activity was evaluated in the combustion of ethanol and n-hexane founding a relationship between the conversion and the catalyst surface vacancies.