High density storage of clean energy fuel gases in soft nanospaces

研究了单壁碳纳米管（SWCNT）、单壁碳纳米角（SWCNH）和金属有机骨架（MOF）的柔软性及其作为清洁能源存储材料的重要影响因素。综述了碳纳米管（SWCNT）和碳纳米管（SWCNH）等碳材料的吸氢性能，碳纳米结构对超临界氢的浓集作用较强，在77 K时具有类液体的吸附密度。超微孔的减少和增加使77K时的吸氢量明显增加。如HNO_3和H_2SO_4的混合酸处理使单壁碳纳米管束的超微孔率大大增加，吸氢量增加一倍。实验和理论研究了纳米曲率对单壁碳纳米管内外表面氮分子单层结构的影响，结果表明，单壁碳纳米管内表面的氮分子单层具有比外表面更长的有序度.单壁碳纳米管拉曼光谱的径向呼吸模式被筛选到一个高频侧的醇分子的吸附，表明单壁碳纳米管的表面是非常敏感的纳米环境。同时，这种效应支持SWCNT壁的柔软性。SWCNH由于采用单壁框架，因此极有希望设计出高性能超级电容器。虽然合成了显示“门吸附”的新的MOF，但在77 K下的氢吸附量小于纳米结构碳。

The soft nature of single wall carbon nanotube (SWCNT), single wall carbon nanohorn (SWCNH) and metal organic framework (MOF) and the important factor for clean energy storage on SWCNTs and MOFs were studied. The hydrogen adsorption capacity of various carbon materials including SWCNT and SWCNH was summarized; concentration effect of supercritical hydrogen with nanostructures of carbon is intensive to give the liquid like density of adsorbed density at 77 K. The defluorination and increase of ultramicroporosity enhance hydrogen adsorption amount at 77 K evidently. For example, the ultramicmporosity of SWCNT bundles is highly increased by HNO_3 and H_2SO_4 mixed acid treatment, giving twice of hydrogen adsorption amount. The effect of nanoscale curvature on the monolayer structure of nitrogen on the internal and external SWCNT surfaces was examined experimentally and theoretically, showing that the monolayer on the internal tube surface has a longer range ordering than that on the external surface. The radial breathing mode of SWCNT Raman spectra is sifted to a high frequency side on adsorption of alcohol molecules, showing that surface of SWCNT is very sensitive to nanoscale environments. At the same time, this effect supports softness of SWCNT wall. The SWCNH is strongly hopeful to design a high performance supercapacitor because of the single wall frame. Although new MOF showing "gate adsorption" is synthesized, the hydrogen adsorption amount at 77 K is smaller than nanostructured carbons.