活性碳纳米管的制备及其结构的研究

采用KOH对催化裂解法制备的碳纳米管进行活化处理，以提高碳纳米管的比表面积，并调整孔结构。研究了活化温度和碱用量对活化碳纳米管的收率、比表面积、晶体结构、微观形貌和孔结构的影响。实验结果表明，通过KOH活化能有效地提高碳纳米管的比表面积，调整孔隙结构。随活化温度升高，活化碳纳米管的收率逐渐降低，比表面积和孔容则逐渐提高。通过活化，碳纳米管的内孔得到释放，有大量的微孔、中孔结构形成。增大碱用量时，收率降低，而比表面积和微孔孔容增加，在比值为7：1时比表面积达到最大值。通过研究发现，制备高比表面积碳纳米管的优化工艺条件为：KOH／CNTs的质量比为7：1，活化温度为900℃。此条件下所得碳纳米管的比表面积为360．1m^2／g，比未活化碳纳米管的比表面积(24．5m^2/g）提高了14倍。

Study of preparation and structures of the activated carbon nanotubes

Carbon nanotubes (CNTs) prepared by catalytical pyrolysis were activated by KOH to increase the specific surface area (SSA) and to modify the pore structures. The effects of the activation temperature and KOH/CNT ratio on the yields, SSA, crystal structure, microstructures and porous structures of CNTs were investigated by an adsorption method, XRD, TEM and HRTEM. Results showed that activation could effectively increase SSA and modify the pore structures of the CNTs. With an increase in activation temperature, SSA and the pore volume increased, while the yield decreased. Through activation, the inner hollow tubes of CNTs were released, and a large quantity of micropores and mesopores was created. With the increase of the KOH/CNT ratio, SSA and micropore volume increased to a maximum at a KOH/CNT ratio of 7∶1, while the yield decreased monotonically. The optimum activation condition to produce activated CNTs with high SSA was found at an activation temperature of 900℃ and a KOH/CNT ratio of 7∶1. SSA of CNTs activated at the optimal condition is 360.1m2/g, which is 14 times larger than that of the non-activated CNTs (24.5m2/g).