LaAl_(1/3)Fe_(2/3)O_3 催化剂上正己烷裂解制备碳纳米管研究

Preparation of carbon nanotubes from catalytic decomposition of n-hexane on LaAl_(1/3)Fe_(2/3)O_3 catalyst

用硝酸镧、硝酸铝与硝酸铁作原料采用柠檬酸法制备了纳米铁铝酸镧催化剂,以正己烷作碳源催化裂解制备了高产率管径均匀的碳纳米管。实验考察了裂解温度、裂解时间和氢气气氛对碳纳米管形貌、产率、直径分布等的影响,采用透射电镜、扫描电镜对碳纳米管进行了表征。结果表明氢气气氛对正己烷催化裂解制备碳纳米管有明显影响,较好的裂解条件是:温度为1 023 K,时间为 45 min,氢气含量为30％;此时碳纳米管管径较小、分布比较均匀。

Nanocrystalline LaAl_(1/3)Fe_(2/3)O_3 was synthesized by the citrate method with La(NO_3)_3·6H_2O, Fe(NO_3)_3·9H_2O Al(NO_3)_3·9H_2O and citric acid as raw materials. The carbon nanotubes from catalytic decomposition of n-hexane were obtained using LaAl_(1/3)Fe_(2/3)O_3 catalyst. The effects of decomposition temperature, decomposition times and hydrogen concentration on the carbon nanotubes were studied. The morphological structure of the carbon nanotube was characterized by SEM and TEM. The results show that the effect of hydrogen concentrations on the carbon nanotubes is sensitive; the decomposition conditions are op- timized as follows: the decomposition temperature of 1 023 K, decomposition time of 45min and hydrogen concentration of 30%. Carbon nanotubes of high purity and well-proportioned diameter can be prepared by this method.