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通过溶胶 -凝胶超临界干燥技术制备出NiO SiO2 比为 1.2的二元气凝胶纳米催化剂 ,并以气凝胶为催化剂通过化学气相热解法合成了碳纳米管 ;碳纳米管的合成是在石英管式炉中完成。将催化剂置于石英舟中 ,在流动氮气中将管式炉加热至所需的温度 ,然后通入甲烷、氢气混合气体 ,热解反应 30min～ 6 0min后形成碳纳米管。反应结束后 ,生成的碳纳米管在氮气氛中冷却至室温。采用XRD、SEM、TEM、HRTEM、Raman分析手段对制得的碳纳米管进行了表征 ,并测定其磁化系数。结果表明 :裂解产物主要由碳纳米管和纳米镍粒子组成 ,且纳米镍粒子包覆于碳纳米管的顶端。这种包覆纳米镍粒子的碳纳米管的比饱和磁化强度和矫顽力分别为 0 .6 6A·m2 ·kg- 1 和2 0 15 7A·m- 1 。
A binary aerogels nanocatalyst with NiO SiO2 ratio of 1.2 was prepared by sol-gel supercritical drying technique and carbon nanotubes were synthesized by chemical vapor phase pyrolysis using airgel as a catalyst. The synthesis of carbon nanotubes Quartz tube furnace completed. The catalyst is placed in a quartz boat, and the tube furnace is heated to the required temperature in flowing nitrogen gas, and then methane and hydrogen mixed gas are introduced into the catalyst to form carbon nanotubes after pyrolysis reaction for 30min to 60min. After the reaction was completed, the resulting carbon nanotubes were cooled to room temperature in a nitrogen atmosphere. The prepared carbon nanotubes were characterized by XRD, SEM, TEM, HRTEM and Raman analysis, and their magnetization coefficients were measured. The results show that the pyrolysis products mainly consist of carbon nanotubes and nano-nickel particles, and the nano-nickel particles are coated on the top of the carbon nanotubes. The specific saturation magnetization and the coercive force of the carbon nanotubes coated with nano-nickel particles are respectively 0.6,6 m2 · kg-1 and 2 0,15 7A · m-1.