纳米碳管储氢机理的电化学研究

ELECTROCHEMICAL STUDY OF HYDROGEN STORAGE MECHANISM OF CARBON NANOTUBES

对流动催化剂法制备的平均直径为6nm的多壁纳米碳管(Multi walledcarbonnanotubes,MWNTs)进行纯化处理,提纯后的多壁纳米碳管利用透射电镜(TEM)表征和电化学储氢研究,同时对该纳米碳管电极进行了自放电实验。结果表明:多壁纳米碳管具有很高的电化学储氢容量(739mAh g),但氢与多壁纳米碳管之间的作用力很微弱,氢很容易从多壁纳米碳管中逃逸出。另外,通过对多壁纳米碳管的气相储氢性能的测试,根据实验结果推测:纳米碳管电化学储氢和气相储氢的主要吸附机理相同,即都是物理吸附。

Purified multiwalled carbon nanotubes (MWNTs) with an average outer diameter of 6?nm and a high purity of 95?w/%, synthesized by a floating catalyst method, were employed for electrochemical hydrogen storage experiments, which were conducted at room temperature and atmospheric pressure. A discharge capacity of 739?mAh/g, corresponding to a hydrogen storage capacity of 2.68?w/% normalized to the weight of MWNTs, was obtained. The selfdischarge experimental results show that the cohesive force between hydrogen and the MWNTs is so weak that hydrogen can easily escape from the MWNTs when the charge process stops, and this result implies that the mechanism for electrochemical storage of hydrogen in MWNTs may be mainly physical adsorption. In addition, the volumetric measurement results also support a physical adsorption mechanism for gas phrase hydrogen storage in the same purified MWNTs. Therefore, electrochemical hydrogen storage and gasphase storage of hydrogen in purified MWNTs share the same mechanism, i.e. mainly physical adsorption.