堇青石载镍催化剂对燃烧合成碳纳米管的影响

借助于硝酸镍溶液, 利用浸渍法在堇青石表面均匀负载镍催化剂颗粒, 在甲烷扩散火焰中活化并催化生成碳纳米 管. 实验结果表明, 生成的多壁碳纳米管直径为30～50nm, 长度约为十几微米, 空腔比较小, 管壁石墨结晶结构良好.提高浸渍液浓度, 催化剂颗粒尺寸明显变大, 但对碳纳米管的形态影响比较小. 延长浸渍时间, 可使催化剂颗粒密度提高, 碳纳米管出现成束生长现象. 结合碳管成核生长过程和火焰燃烧的特点, 探讨了催化剂对于碳纳米管生长的影响机制.

Effects of Ni Coated Cordierite Catalyst on Flame Synthesis of Carbon Nanotubes

Catalyst particles coated uniformly on cordierite surface through dipping-method in nickel nitrate solution, were used to synthesize carbon nanotubes via methane diffusion flame method. Well-graphitized carbon nanotubes were synthesized with outer diameters of 30--50nm and length of tens of micron meter. The results show that diameters of carbon nanotubes are not affected by the size of particles on substrate surface, which increase with the concentration of dipping solution. When catalyst particles become denser with dipping time extending, the density of carbon nanotubes increases obviously with bound morphology. The catalytic mechanism is discussed in detail to propose the growth of carbon nanotubes and suggests the possible changes of particles during this process.