碳纳米管的高温处理及表征

用真空高温炉对在纳米聚团流化床中用催化裂解法大批量制备的多壁碳纳米管进行了1500～2150℃的真空高温处理,并用高分辨透射电镜、激光拉曼、X射线晶体衍射及热重分析表征热处理效果.结果证明,高温处理对碳纳米管具有显著的整形作用,激光拉曼光谱可以有效地表征高温整形效果,但是管壁的大缺陷很难得到修复.经过1800℃处理以后,碳纳米管中的金属催化剂和载体得到有效去除,产品纯度高达99%以上.

High Temperature Treatment and Characterization of Carbon Nanotubes

Multi-walled carbon nanotubes(MWNTs) produced by the catalytic chemical vapor deposition(CCVD) method in a nano-agglomerated fluidized-bed reactor(NAFBR) have been treated in a vacuum furnace at the temperatures between 1 500 and 2 150 ℃. High resolution transmission electron microscopy(HRTEM), laser Raman spectroscopy, X-ray diffraction(XRD) and thermogravimetric analysis(TGA) were performed to characterize the annealed and purified MWNTs. The results reveal that the graphite layers of the tube-walls are more regular after the high temperature treatment, which can be characterized by Raman analysis. However, large defects in tube-walls can not be healed completely. Heating the nanotubes up to 1 800 ℃ essentially results in the removal of nanometer catalyst particles, and MWNTs with a purity of more than 99% can be obtained.