采用气凝胶与干凝胶两种催化剂载体通过化学气相淀积方法制备出螺旋状的碳纳米管.研究结果表明:气凝胶催化剂载体所制备出的螺旋碳纳米管和干凝胶载体所制备出的螺旋碳管相比较具有以下几个特点:(1)较好的石墨化程度,(2)较小的直径,(3)较好的螺旋形态,即较好的螺距一致性.分析结果认为气凝胶独特的介孔性质是导致气凝胶样品所制备的碳管具有以上特点的根本原因.另外,还提出催化剂颗粒周边上催化活性的各向异性将导致螺旋碳管的生长.
Helical carbon nanotubes were synthesized by a chemical vapour deposition method from both silica aerogels and silica xerogels containing catalysts.
The research result shows that the helical carbon nanotubes prepared from the silica aerogels have the following pecularities compared with those from
silica xerogels: (1) more degree of graphitization; (2) smaller diameter; (3) better helical shape, namely, the more identical pitch. The peculiar
mesoscopic properties of aerogels are responsible for those above pecularties of helical carbon nanotubes prepared from silica aerogels when compared
with those from xerogels. What’s more, the anisotropy of catalytic activity of the catalyst particles leads to the growth of helical carbon nanotubes.
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