Synthesis, Characterization, and Catalytic Activity of Mn-doped Perovskite Oxides for Three-Way Catalysis

Mn-doped La 0.8 Sr 0.2 CoO 3 perovskite oxides (La 0.8 Sr 0.2 Co 1– x Mn x O 3 ; x = 0, 0.1, 0.3, 0.5) were synthesized by a modified sol-gel method. The phase-pure oxides were obtained. CoO and carbonates were formed on the surface of La 0.8 Sr 0.2 CoO 3 . With increasing doping content, these impurities were reduced while the stability of the perovskite structure was improved. The valence state of B-site ions and the amount of absorbed oxygen were influenced by Mn doping. The catalytic activity of the perovskite catalysts was investigated for CO oxidation and simultaneous removal of CO, C 3 H 8 , and NO. For CO and NO removal, La 0.8 Sr 0.2 Co 0.9 Mn 0.1 O 3 exhibited the best performance. For C 3 H 8 removal, the reactivity was promoted linearly with the doping content. The structure-activity relationship is also discussed.