MXene molecular sieving membranes for highly efficient gas separation

2022 09/26

(Nat. Commun.,2017,DOI: 10.1038/s41467-017-02529-6)

This paper introduces a two-dimensional lamellar molecular sieve membrane MXene with highly ordered subnano channels. The abundant and evenly distributed end groups on the surface of MXene nanosheets are used to support the formation of highly ordered two-dimensional lamellar nanoporous channels, so as to achieve rapid and accurate gas separation capability: H2 permeation flux reached 2200 Barrer, and H2/CO2 separation selectivity reached 160. Molecular dynamics quantitative simulation was used to verify the experimental results. The development of MXene 2D materials with two-dimensional structures and tunable physicochemical properties as novel molecular sieve membranes provides exciting opportunities in the field of membrane separation. There are now more than 30 classes of MXenes materials available, and dozens more MXenes can be prepared, which provides a lot of room to further improve their separation performance. The MXene membrane developed in this paper is very important for gas separation, such as H2 purification in methanol reforming process, CO2 capture in zero-emission fossil fuel power generation process, H2 recovery in ammonia production, etc. In addition, a new concept on the structural design of two-dimensional molecular sieve membranes was demonstrated, namely, the use of highly ordered two-dimensional nanochannels can achieve rapid and accurate molecular sieve separation, break the trade-off limit, and improve the separation efficiency.

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