Zou Lianli, Hou Chun-Chao, Liu Zheng, Pang Huan, Xu Qiang
Research Institute of Electrochemical Energy , National Institute of Advanced Industrial Science and Technology (AIST) , Ikeda, Osaka 563-8577 , Japan.
Graduate School of Engineering , Kobe University , Nada Ku, Kobe , Hyogo 657-8501 , Japan.
J Am Chem Soc. 2018 Nov 14;140(45):15393-15401. doi: 10.1021/jacs.8b09092. Epub 2018 Nov 2.
Nanotubes have attracted great attention. Here, we report the fabrication of the first single-crystal metal-organic framework (MOF) nanotubes. Superlong single-crystal cobalt-organic framework (Co-MOF) nanotubes, which have a diameter of ∼70 nm and length of 20-35 μm with parallel multichannels (window size: 1.1 nm), have been successfully synthesized via an amorphous MOF-mediated recrystallization approach. The synthesized MOF nanotubes can be used as a nanocolumn for separation of large molecules. Carbonization of the Co-MOF nanotubes in an argon atmosphere preserves the 1D morphology, affording long carbon nanofibers. A hierarchical architecture composed of carbon nanofibers wrapped by carbon nanotubes (20-30 nm in diameter and 200-300 nm in length) with cobalt nanoparticles on the top is formed by the carbonization of the Co-MOF nanotubes along with dicyandiamide as a nitrogen and a secondary carbon source. The resulting hierarchical dendrites with carbon nanofiber trunks and carbon nanotube branches exhibit excellent electrocatalytic activity for oxygen reduction reaction and exceptional applications in rechargeable Zn-air batteries. This work demonstrates a new strategy to fabricate MOF nanotubes and relative 1D nanostructures.
纳米管已引起了极大关注。在此，我们报道了首例单晶金属有机框架（MOF）纳米管的制备。通过非晶态MOF介导的重结晶方法，成功合成了超长单晶钴有机框架（Co-MOF）纳米管，其直径约为70 nm，长度为20 - 35 μm，具有平行的多通道（窗口尺寸：1.1 nm）。合成的MOF纳米管可用作分离大分子的纳米柱。在氩气气氛中对Co-MOF纳米管进行碳化可保留一维形态，得到长碳纳米纤维。通过Co-MOF纳米管与作为氮源和二次碳源的双氰胺一起碳化，形成了一种由直径为20 - 30 nm、长度为200 - 300 nm的碳纳米管包裹碳纳米纤维且顶部带有钴纳米颗粒组成的分级结构。所得具有碳纳米纤维主干和碳纳米管分支的分级树枝状结构对氧还原反应表现出优异的电催化活性，并在可充电锌空气电池中具有特殊应用。这项工作展示了一种制备MOF纳米管及相关一维纳米结构的新策略。
