PREPARATION AND CATALYTIC PERFORMANCE OF La0.5RE0.1Sr0.4MnO3 (RE: Y, Dy, Sm OR Ce) ULTRA-FINE PARTICLES in METHANE COMBUSTION

Ultra-fine particles of La_0.5RE_0.1Sr_0.4MnO₃ (RE: Y, Dy, Sm or Ce) with perovskite structure were prepared by the co-precipitation method, resulting in high surface area and good thermal stability catalysts (S_BET reached 45 and 16.5 m²/g, upon calcination at 700 and 1000^oC, respectively). The thermal stability of these ultra-fine particles was effectively improved with partial substitution of RE³⁺ (Y³⁺, Dy³⁺, or Sm³⁺) for La³⁺ in La_0.6Sr_0.4MnO₃. The catalysts exhibited high activity for the total combustion of methane. For the catalysts calcined at 1000^oC, La_0.5RE_0.1Sr_0.4MnO₃ (RE: Y or Dy) were much more active and showed much higher specific surface area than La_0.6Sr_0.4MnO₃.