【摘要】 采用溶胶 -凝胶、超临界干燥法制备了Al2 O3气凝胶负载钴催化剂 ,对该催化剂进行了物化性质表征和甲烷催化裂解反应的活性评价。分别考察了煅烧温度、反应温度对催化剂活性及生成碳纳米管形态的影响。煅烧后的Al2 O3气凝胶负载钴催化剂具有CoAl2 O4 尖晶石结构。Al2 O3气凝胶负载钴催化剂的积碳活性与还原后得到的金属催化剂的量成正比 ,随反应温度的升高 ,碳纳米管生长速率升高 ,催化剂失活速率同步加快 ,催化剂积碳活性下降。Al2 O3气凝胶负载钴催化剂在低温下具有较高的活性。在该催化剂上生长出的碳纳米管形态单一 ,均为弯曲、中空管状。碳纳米管内外壁光滑 ,管径均匀 ,随反应温度升高 ,碳纳米管直径变细。 62 5℃时 ,获得的碳纳米管直径在 8～ 1 0nm左右更多还原

【Abstract】 An alumina supported cobalt aerogel catalyst was prepared with a sol-gel and supercritical drying method and was used in the catalytic decomposition of methane. The characterization of the physical and chemical properties of this catalyst and tests of its reactivity for catalytic decomposition of methane were investigated. The effects of calcination and reaction temperatures on the reactivity of the catalyst and the morphology of carbon nanotubes were studied. It has been observed that the catalyst oxide precursor has a CoAl 2O 4 structure. The reactivity of the catalyst increases with the amount of reduced cobalt metal in the catalyst. The growth and deactivation rate increase with the reaction temperature, and the reactivity of the catalyst decreases with the reaction temperature. An alumina supported cobalt aerogel catalyst has a high reactivity at low reaction temperature. TEM micrographs show that the carbon nanotubes obtained at 625 ℃ are hollow and curved with diameters in the range of 8～10 nm. Carbon nanotubes have even diameter and slick inner and outer wall. The diameters of the carbon nanotubes decrease with reaction temperature.更多还原