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Résumé :
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Perovskite-type catalysts group one Ln0.6Sr0.4FexCo1−xO3 (Ln = Nd, Pr, Gd, Sm, La, 0 < x < 1), (La0.8Sr0.2)0.9MnO3 and La0.8Sr0.2CrO3, and group two sodium-doped ACoO3 (Na:A = 1:4) and A0.8Na0.2MnO3 (A = La, Gd, Sm) were synthesized, and their properties for activation of methane were evaluated in a quartz reactor first. Catalysts group one presented much higher activity than catalysts group two at temperatures below 740 °C, and the main product was, however, carbon dioxide. Group two showed much higher selectivity to C2 hydrocarbons than group one. Electrochemical measurements were conducted in a solid oxide membrane reactor with sodium-doped LaCoO3 as the catalyst electrode. It was found that electrochemical supply of O2− to the catalyst film can significantly change the rate of methane consumption and C2 hydrocarbon selectivity. The total selectivity to C2 hydrocarbon exceeded 80% in the case of the electrochemical supply of oxygen. On the basis of the experimental results, a kinetic model was suggested to describe the reaction results.
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