Study On Synthesis Of Carbon Nanotubes By Pulsed Laser Ablation For In-Situ Growth Method And CVD Supporting Method

Carbon nanotubes were separately synthesized by a new pulsed laser ablation (PLA) for in-situ growth method and CVD support method in this paper. FT-IR, UV-Vis, XFS, LAMAN, TEM, XRD, BET methods were used to characterize the sol, carbon nanotube and other products in the experiment.In the PLA method, the sols containing carbon nanotubes were successively obtained by using 1064nm pulsed laser to ablate the interface of Fe/C, or Ni/C targets and ethanol under common temperature and pressure, and then carbon nanotubes were directly acquired by evaporating the ethanol. The effects of different pulsed laser intensities and catalysts on making carbon nanotubes were systematically investigated. The results show that the better pulsed laser intensity to make the sols is 4.5×109W/cm2. The observation of TEM shows the curve carbon nanotubes with 15-45nm in diameter and above 1μm in length are in-situ synthesized successfully by PLA using Fe or Ni as catalysts. In addition, some ablation products such as carbon fibers and carbon nano-paticals etc. are found. Especially, some special nanotubes states can be also observed as Ni catalyst. The results also show that the output and quality using Ni as catalyst are better than that using Fe catalyst. In CVD support method, carbon nanotubes were prepared with the supported Fe catalyst on the regular mesoporous molecular sieve MCM-41 by catalytic pyrolysis of C2H2. The author studied systematically the effect of different react conditions on the structure, property and thermal-stability of MCM-41, and reached an optimum condition of prepared MCM-41, whose mesoporous diameter was about 2.9nm, with 0.12 C16TMABr: 1TEOS: 0.24NaOH: 66.7H2O under hydro-thermal condition. Carbon nanotubes obtained using this way shows the features of small even diameter and short length.