催化剂组分对制备单壁碳纳米管的影响

利用柠檬酸法制备出了Mo-Fe-MgO，Mo-Co-MgO和W-Co-MgO催化剂，在小型流化床中，以Ar气为载气，在1123 K下催化裂解CH₄来制备单壁碳纳米管(SWCNTs).利用透射电子显微镜和拉曼光谱方法研究了催化剂组分对SWCNTs制备的影响，并对SWCNTs的生长机理进行了探索，研究结果表明，柠檬酸法是一种制备负载型SWCNTs催化剂的有效方法，三种催化剂都能够得到质量较好的SWCNTs,在1123 K左右，SWCNTs在三种催化剂上的生长过程可能类似于“微液相模型”.催化剂的组分对SWCNTs的管径分布影响较小，不同催化剂所得到的SWCNTs在内部结构上存在一定的差异.催化剂中加入第二组分Mo和W能有效提高产物的碳产率.关键词：单壁碳纳米管催化化学气相沉积法生长机理拉曼光谱

The effect of composition of the catalysts on the preparation of single-walled carbon nanotubes

The Mo-Co-MgO and W-Co-MgO catalysts were first prepared by the citric acid method.The single-walled carbon nanotubes(SWCNTs)were synthesized by decomposing CH_4 in Ar over the Mo-Fe-MgO,Mo-Co-MgO and W-Co-MgO catalysts at 1123 K in the fluidized bed reactor.The effects of composition of the catalysts on the synthesis of SWCNTs were studied by Raman spectroscopy and transmission electron microscopy(TEM).And the mechanism of growth of SWCNTs was discussed.The results show that the citric acid method is effective for to preparing the catalysts and the high-quality SWCNTs were synthesized over the three catalysts.At 1123 K,the growth of SWCNTs over the catalysts may be similar to the liquid micro-area model.The dependence of diameter distribution on the composition of the catalysts was weak.There were some differences in the inner structure of SWCNTs synthesized over the three different catalysts.The carbon yield rates of products were increased by the addition of W and Mo in the catalysts.