Two-dimensional nanosheet-based gas separation membranes

Two-dimensional (2D) materials of nanosized thickness are emerging building blocks for designing membranes with superior performance (i.e. high gas permeation flux and selectivity), as a result of their unique nanostructures. In this review, we discuss the recent breakthroughs in the synthesis of 2D nanosheets and the preparation of 2D nanosheet-based gas separation membranes, focusing on the synthetic methods for preparing 2D nanosheets (covering inorganics, hybrids, carbons and organics), the structural properties of 2D nanosheets, the fabrication methods of 2D nanosheet-based membranes, and their performance in gas separation. The current technical limitations and future research directions in this field are also discussed.