Mesoscopic cage-like structured single-wall carbon nanotube cryogels
Mesoscopic cage-like structured single-wall carbon nanotube cryogels
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DOI：
10.1016/j.micromeso.2019.109814
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发表时间：
2020-02-01
影响因子：
5.2
通讯作者：
Kaneko, Katsumi
中科院分区：
文献类型：
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作者：
Kamijyou, Yuito;Stevic, Dragana;Kaneko, Katsumi
我们使用高浓度的 SWCNT 水墨水并借助 Zn-Al 溶胶凝胶分散剂制备了具有超微孔颈部的介观笼状结构单壁碳纳米管 (SWCNT) 冷冻凝胶。高分辨率透射电子显微镜（TEM）图像显示SWCNT冷冻凝胶中存在三维笼状结构，这与原始SWCNT的束结构有很大不同。根据 TEM 观察，SWCNT 冷冻凝胶的平均束尺寸比原始 SWCNT 小 30%。 SWCNT 冷冻凝胶和原始 SWCNT 的 N-2 在 77 K 和 Ar 在 87 K 的吸附等温线在低和高相对压力区域具有明显的吸附滞后，表明颈缩超微孔和中孔的存在。 Ar 吸附等温线表明，SWCNT 冷冻凝胶具有显着的低和高相对压力滞后，表明存在具有颈缩超微孔入口的中孔。 Ar 和 N-2 吸附的 SWCNT 冷冻凝胶的表面积大约是原始 SWCNT 的两倍，这与 SWCNT 束的几何评估表面积一致。通过吸附 N-2 和 Ar 评估的中孔体积在 15 nm 以上的中孔范围内分别比原始 SWCNT 大 3 倍和 2.3 倍。通过冷冻干燥，SWCNT 组件的介孔率显着增加，支持了 TEM 观察到的介观三维笼状结构。
We fabricated mesoscopic cage-like structured Single-Wall Carbon Nanotube (SWCNT) cryogels having ultra-microporous necks using highly concentrated SWCNT-water inks with the aid of Zn-Al sol-gel dispersant. High-resolution transmission electron microscopy (TEM) image shows the presence of three-dimensional cage-like structures in the SWCNT cryogels, which are quite different from the bundle structures of pristine SWCNTs. Average bundle size of the SWCNT cryogels is 30% smaller than that of pristine SWCNTs according to the TEM observation. Adsorption isotherms of N-2 at 77 K and Ar at 87 K for SWCNT cryogels and pristine SWCNTs have explicit adsorption hysteresis in low and high relative pressure regions, indicating the presence of necked ultramicropores and mesopores. Ar adsorption isotherms show that the SWCNT cryogels have predominant low and high relative pressure hysteresis, suggesting the presence of mesopores with necked entrances of ultramicropores. Surface areas of SWCNT cryogels by Ar and N-2 adsorption are about two times larger than those of pristine SWCNTs which is in agreement with the geometrically evaluated surface area from SWCNT bundles. Mesopore volumes evaluated by adsorption of N-2 and Ar are 3 and 2.3 times larger than those of pristine SWCNTs in the mesopore range above 15 nm. The marked increase in the mesoporosity of the SWCNT assemblies by freeze-drying supports the mesoscopic three-dimensional cage-like structures observed by TEM.