MXene molecular sieving membranes for highly efficient gas separation

• Published in: Nature communications Vol. 9; no. 1; p. 155
• Main Authors: Ding, Li, Wei, Yanying, Li, Libo, Zhang, Tao, Wang, Haihui, Xue, Jian, Ding, Liang-Xin, Wang, Suqing, Caro, Jürgen, Gogotsi, Yury
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.01.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 147/28; 639/166/898; 639/301/299/1013; 639/638/298; 639/925/357/1018; Carbon dioxide; Energy efficiency; Gas separation; Humanities and Social Sciences; Interlayers; Lamellar structure; Mass transport; Membrane permeability; Membranes; Molecular dynamics; multidisciplinary; MXenes; Nanochannels; Nanostructure; Permeability; Science; Science (multidisciplinary); Selectivity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02529-6

Molecular sieving membranes with sufficient and uniform nanochannels that break the permeability-selectivity trade-off are desirable for energy-efficient gas separation, and the arising two-dimensional (2D) materials provide new routes for membrane development. However, for 2D lamellar membranes, disordered interlayer nanochannels for mass transport are usually formed between randomly stacked neighboring nanosheets, which is obstructive for highly efficient separation. Therefore, manufacturing lamellar membranes with highly ordered nanochannel structures for fast and precise molecular sieving is still challenging. Here, we report on lamellar stacked MXene membranes with aligned and regular subnanometer channels, taking advantage of the abundant surface-terminating groups on the MXene nanosheets, which exhibit excellent gas separation performance with H 2 permeability >2200 Barrer and H 2 /CO 2 selectivity >160, superior to the state-of-the-art membranes. The results of molecular dynamics simulations quantitatively support the experiments, confirming the subnanometer interlayer spacing between the neighboring MXene nanosheets as molecular sieving channels for gas separation. Two-dimensional materials show great potential for membrane technologies, but their disordered channels hinder their molecular sieving performance. Here, Wang, Gogotsi and colleagues design a MXene membrane with ordered nanochannels that exhibits an excellent H 2 /CO 2 gas separation performance.