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以稀土合金MlNi5-1.35(CoAlMn)1.35为催化剂,C2H2为碳源,H2为还原气和载气,用CVD法合成了纯度较高的CNTs。通过用SEM,TEM,XRD及Raman等表征测试方法,研究了H2流量对合成的CNTs管径、产量、纯度、形态及石墨化程度的影响。结果表明:合金催化剂经还原后其粒径从μm级细化到了nm量级;在催化剂与C2H2反应过程中不通入H2时,催化剂上仍能生长出CNTs,但其长度短而管径粗(约97.8nm),管壁厚而粗糙;随着H2流量增大,CNTs管径先减小后增大,而其产量、纯度及石墨化程度则先提高后下降。当H2流量为50ml·min-1时,CNTs管径达最细(平均管径49.1nm);H2流量为75ml·min-1时,其产物纯度高,产量最大(4.05g·g-1催化剂),CNTs石墨化程度最高;H2流量为100ml·min-1时,CNTs管径最均匀(平均管径97.8nm)。
Rare earth alloy MlNi5-1.35 (CoAlMn) 1.35 as a catalyst, C2H2 as a carbon source, H2 as a reducing gas and a carrier gas, synthesized by high-purity CVD CNTs. The effects of H2 flux on the diameter, yield, purity, morphology and graphitization of CNTs were investigated by SEM, TEM, XRD and Raman characterization. The results show that the particle size of the alloyed catalyst is reduced from μm to nm after the reduction. When the catalyst is not reacted with C2H2, CNTs can still grow on the catalyst but its length is short and the diameter is coarse About 97.8nm), the thickness and roughness of the tube wall; with the increase of H2 flow, the diameter of CNTs first decreases and then increases, while the yield, purity and graphitization first increase and then decrease. When the flow rate of H2 was 50ml · min-1, CNTs had the smallest diameter (average diameter 49.1nm). When the flow rate of H2 was 75ml · min-1, the purity and yield of CNTs were the highest (4.05g · g-1) ), The highest degree of graphitization CNTs; H2 flow of 100ml · min-1, CNTs most uniform diameter (average diameter 97.8nm).