Catalytic Activity of La_(1-x)Sr_xCoO_3 (x=0.2-0.8) Supported on Porous Mullite Fiber Ceramics for NO and CO

Perovskite La1-xSrxCoO3 (x=0.2,0.4,0.6,0.8) catalysts based on porous mullite fiber ceramic were prepared by a vacuum impregnation method. The samples were characterized by XRD, SEM and BET, respectively. The La(OH)3 crystal phase was detected besides the perovskite structures in La1-xSrxCoO3 catalysts, and the La(OH)3 peaks become sharp as x decreases. Tridimensional net-shape of support and the good dispersing particles of catalysts based on support were detected by SEM. Specific surface area of La1-xSrxCoO3 increases with the degree of substitution x of Sr for La via BET tests. Catalytic activity of La1-xSrxCoO3 catalysts prepared for CO+NO was tested. The results indicate that La1-xSrxCoO3 catalysts have a best catalytic activity, when partial substitution of Sr for La reaches the optimal substitution fraction (x=0.2).