Two-dimensional (2D) material nanosheets have been widely investigated for gas separation due to their atomic thick layered structures. For 2D nanosheet, there mainly are two transport paths for the gas: (1) the pores in the nanosheet plane; and (2) the nanoslits constructed by layer-stacked nanosheets. The in-plane pores separate the gases by size-exclusion or functional groups on the pores. The 2D nanoslits in layer-stacked nanosheets have a much longer path than the in-plane pores and have more complex transport mechanisms. Herein, we have summarized the construction of 2D nanoslits and mechanisms for gas transport. A newly developed composite membrane based on the 2D framework is also highlighted. The transport mechanisms in a variety of 2D materials are also introduced.

二维（2D）材料纳米片由于其原子厚的分层结构而被广泛研究用于气体分离。对于2D纳米片，主要有两种气体传输路径：（1）纳米片平面中的孔；（2）由层状堆叠的纳米片构成的纳米缝。平面内的孔通过尺寸排阻或孔上的官能团将气体分开。叠层纳米片中的2D纳米缝比平面内的孔具有更长的路径，并且具有更复杂的传输机制。在这里，我们总结了二维纳米缝的构造和气体传输的机理。还重点介绍了基于2D框架的新开发的复合膜。还介绍了各种2D材料中的传输机制。