Preparation And Properties Of Aligned Carbon Nanotubes Array Study

A non-template CVD method was used to synthesize well-aligned carbon nanotube (ACNT) arrays. Ferrocene was as a catalyst, xylene as carbon source. This was carried out in a single-furnace system. The products were characterized by Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM), Energy Dispersive Spectrometer(EDS) and Raman Spectroscopy. The effects of process parameters on ACNT arrays growth were also investigated. These results show that well-aligned carbon nanotubes can easily grow on silicon substrate between the temperature of 780～840°C with catalyst concentration of 0.01～0.03 mg/1. Under above condition the growth rate of ACNT can reach 25μm/min.ACNT arrays were treated by oxidation method with concentrated nitric acid, and the adsorption of p-nitrophenol on ACNT arrays before and after concentrated nitric acid treatment has been compared by Raman,SEM and spectrophotometer. It was found from the results of Raman and SEM that the CNTs were cut and opened, in addition, the hydroxyl groups were introduced by nitric acid. The concentration of p-nitrophenol were determined by spectrophotometer, and their adsorption capacities at different concentration were worked out. The result indicates that the adsorption capacity of ACNT arrays after concentrated nitric treatment is obviously enhanced.The gas-sensitivity to ethanol of CNTs treated by concentrated nitric acid, CNTs and ACNT arrays was discussed. It was found that ACNT arrays has the lowest sensitivity to ethanol gas, and the response time is the shortest. However the sensitivity of CNTs treated by concentrated nitric acid is the highest, and the response time is the longest.