Controlled Fabrication And Catalytic Oxidation Properties Of Specially-shaped Nanostructured Oxides

In view of the current technological bottleneck in facile and high-efficient fabrication of nanostructured oxide catalysts,in the dissertation,flower-like CuO/MgO and Co₃O₄/MgO supported catalysts as well as flower-like Mg_1-XNi_XO solid solutions were fabricated via the controlled calcination of the precursors derived from a self-sacrificed template method for the first time.The effects of molar ratio between M²⁺?M=Cu,Co,Ni?and Mg?OH?₂ in the solutions,calcination temperature on morphology,phase and catalytic properties for oxidation of CO/CH₄ were systematically dealt with.Then,rare earth-doped Co₃O₄ and Ce?Zr_1-?O₂ hollow spheres were prepared via a spray solution combustion method.The effects of the sorts and amounts of doped elements,cationic concentration in reaction solution,temperature and molar ratio of fuel on morphology,phase and catalytic properties for oxidation of CO/CH₄ were systematically investigated.The results indicated that the flower-like CuO/MgO supported catalysts with 2?m in average size and 110.77 m²/g in specific surface area were synthesized by calcination of the Cu?OH?₂/Mg?OH?₂ precursors at 350?,prepared by the self-sacrificed template method in the case of X=10%,presented the lowest temperature of complete conversion for CO at 180 ^oC and found no any activity decrease during 48 h evaluation at 250 ^oC,showing the highest catalytic activity and excellent stability.The flower-like Co₃O₄/MgO supported catalysts with 2?m in average size and 120.47 m²/g in specific surface area were synthesized by calcination of the Cu?OH?₂/Mg?OH?₂ precursors at400 ^oC,prepared by the self-sacrificed template method in the case of X=10%,presented the lowest temperature of complete conversion for CO at 160 ^oC and found no any activity decrease during 48 h evaluation at 250 ^oC,showing the highest catalytic activity and excellent stability.The flower-like Mg_1-XNi_XO solid solutions were fabricated via calcination of the Ni?OH?₂/Mg?OH?₂ precursors,derived from the self-sacrificed template method,indicating the superior catalytic activity for oxidation of CH₄.The X value and calcination temperature have vital effects on the morphology of the resultants.In the case of X>80%,the products present irregular shape as the flower-like template destructed.Finally,Ce_0.1Co_0.9O_1.45 and Ce_0.6Zr_0.4O₂ hollow spheres were fabricated via a spay solution combustion method using glycine as fuel in the case of molar ratio of fuel equal to?₀ and reaction temperature of 800?,presented the lowest temperature of complete conversion for CO at 140 ^oC and 180 ^oC,respectively,showing the highest catalytic activity among the respective series.