Preparation And Structural Analysis Of LaCoO₃ Perovskite CO And NO Elimination

This paper uses ABO3-type perovskite oxide LaCoO3 as model catalyst for study.Effect of preparation methods,molar ratio of La/Co and partial replacement of La by Sr on the physicochemical properties of LaCoO3 and its catalytic performances for CO and NO elimination was investigated.The following achievements were obtained:1.LaCoO3 prepared by carbon template method?LaCoO3_T?is the best catalyst for CO oxidation.2.LaCoO₃ prepared by sol-gel method using ethylene glycol and alcohol mixture as a complexing agent shows good surface area and catalytic performances.3.The formation of perovskite structure relates intimately to the electron distribution in the 3d orbit of the transition metal.The easier the electrons to be initiated,the easier the perovskite structure to be formed.4.The CO oxidation activity obtained from LaCoO₃ supported on the mesoporous silica SBA-15?i.e.,LaCoO3_SBA-15?is similar to that obtained from sample prepared by sol-gel method using ethylene glycol and methanol mixture as a complexing agent?i.e,LaCoO3_EM?,and is better than that obtained from sample prepared using polymethyl methacrylate as soft template?i.e.,LaCoO3_PMMA?.5.For the series Co₃O₄-LaCoO₃ composite oxide catalysts,the sample prepared at La and Co molar ratio of 1:5 shows the highest catalytic activity for CO oxidation and CO+NO reduction.6.For the Ce doping La_1-xCe_xCoO₃ samples,the maximum Ce content is 10 at.%,otherwise CeO2 impurities will be separated.7.For the Sr doping La_1-xSr_xCoO₃ samples,the best surface area and CO oxidation activity is obtained at x=0.4.