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采用沉淀方法制备了直径分布狭窄的均匀Fe3O4纳米颗粒.Fe3O4纳粒形体几近一致,平均粒径为10.33 nm±2.99 nm(平均粒径±标准偏差).在超声作用下将MgO纳米颗粒分散在一定量Fe3O4纳米颗粒的水溶液中获得MgO负载Fe3O4的纳米颗粒.以甲烷为碳源,Fe3O4/MgO为催化剂,经化学气相沉积,在Fe3O4纳粒上制得了大量直径近乎均匀的单壁碳纳米管(SWCNTs)束.TEM显示:SWCNTs的平均直径1.22rm.热重分析显示:样品在400℃～600℃温度区间失重量约19％.拉曼光谱显示:SWCNTs的ID/IG的强度比为0.03,表明采用Fe3O4/MgO催化剂可制得高石墨化程度的单壁碳纳米管.“,”Fe3O4 nanoparticles with a narrow diameter distribution having an average diameter of 10.33 nm±2.99 nm( average diameter±standard deviation) were prepared by a precipitation method.The Fe3O4 nanoparticles were supported on MgO by mixing the MgO nanopowder with the required amount of Fe3O4 nanoparticles in water under extensive sonication.Single-walled carbon nanotubes (SWCNTs) were synthesized by the chemical vapor deposition (CVD) of methane over the Fe3O4/MgO catalyst.Transmission electron microscopy showed that a large number of SWCNT bundles of nearly uniform diameter were produced by the CVD method.The average diameter of the produced SWCNTs was ca.1.22nm.Thermogravimetric analysis showed that the weight loss was approximately 19％ by oxidation of carbon in the temperature range of 400-680 ℃.The ratio of the intensity of the D-band to theG-band was 0.03,indicating that the SWCNTs were well-graphitized.