Synthesis and Purification of Single-Walled Carbon Nanotubes Prepared Over CoO/MgO Aerogel Catalyst

摘要

Using Co(NO_3)_2.6H_20 and Mg(NO_3)_2.6H_20 as precursors, CoO/MgO aerogel was prepared by a supercritical fluid drying method. Single-walled carbon nanotubes (SWNTs) have been synthesized by catalytic decomposition of methane over the CoO/MgO aerogel. The influences of process parameters on the morphology and structure of prepared SWNTs was investigated by FESEM and HRTEM and Raman spectroscopy analysis. The results show that appropriate preparation parameters selection is beneficial to improving the quality and yield of SWNTs. The optimal process for the SWNTs growth is under the mixed atmosphere of CH_4/H_2with flow rate ratio of 2.5/1 at 880 °C for 30 min. The impurities, such as catalytic particles and amorphous carbon in SWNTs, can be removed by air oxidation and further hydrochloric acid treatment. The purity of the final SWNTs is over 92 wt%.