Effect of Nb_2O_5 and SWCNT on the H_2 sorption properties of Mg-based hydrogen storage system

添加氧化鈮和單壁奈米碳管對鎂基儲氫材料性能之影響

莊育賢(Yu-Siang Chuang) ； 黃聖杰(Sheng-Jye Hwang)

《中國機械工程學刊》 35卷4期 (2014/08) Pp. 327-332

摘要

金屬氫化物是一種安全且可行的儲氫技術；鎂是最具有潛力的儲氫金屬之一，其成本低、質量輕、對環境污染小且具有高重量儲氫密度、高體積儲氫密度和可逆的吸放氫特性。在過去的研究顯示，金屬氧化物觸媒Nb_2O_5對於鎂基儲氫材料具有良好的助益效果，然而其球磨時間需大於20小時，不利於商用化和大量生產；因此本研究藉由Mg-Nb_2O_5-SWCNT三元材料混合，希望能夠有效縮短材料的球磨時間。當材料球磨完成後，對所有樣品做SEM，XRD等特性分析與PCT儲氫量之測量。

並列摘要

Metal hydrides are of considerable interest for safe and practical hydrogen storage. Among theses, Mg is regarded as a promising hydrogen storage material due to its high theoretical gravimetric, volumetric capacity and the full reversibility of its sorption reactions combined with low cost, low density and environmental friendliness. In previous studies, the superior catalytic effect of Nb_2O_5 was demonstrated and compared to other metal oxide catalysts. However, the nanocrystalline MgH_2-Nb_2O_5 mixtures must be milled for more than 20 hours to obtain the outstanding sorption kinetics. Long milling time causes high production costs, and makes the system less attractive for commercial applications. In this way, ternary mixtures Mg-Nb_2O_5-SWCNT (molar ratio %=97.5:0.5:2.0) were prepared by high-energy ball milling and their hydrogen storage behaviors were investigated. The structural and phase evolution of SWCNT and Nb_2O_5 were investigated by using X-ray diffractometry (XRD) and morphology by scanning electron microscopy (SEM). Detail sorption mechanisms were discussed to understand the catalytic effect.

並列關鍵字

Mg-based materials ； Hydrogen storage ； Single-walled carbon nanotubes (SWCNT) ； High-energy ball milling