Nanoconfinement enabled non-covalently decorated MXene membranes for ion-sieving

Yuan Kang; Ting Hu; Yuqi Wang; Kaiqiang He; Zhuyuan Wang; Yvonne Hora; Wang Zhao; Rongming Xu; Yu Chen; Zongli Xie; Huanting Wang; Qinfen Gu; Xiwang Zhang

doi:10.1038/s41467-023-39533-y

Nanoconfinement enabled non-covalently decorated MXene membranes for ion-sieving

Nat Commun. 2023 Jul 10;14(1):4075. doi: 10.1038/s41467-023-39533-y.

Authors

Yuan Kang¹, Ting Hu¹, Yuqi Wang², Kaiqiang He¹, Zhuyuan Wang³, Yvonne Hora¹, Wang Zhao¹, Rongming Xu⁴, Yu Chen⁵, Zongli Xie⁶, Huanting Wang¹, Qinfen Gu⁷, Xiwang Zhang^{8

9}

Affiliations

¹ Department of Chemical and Biological Engineering, Monash University, Clayton, VIC, 3800, Australia.
² School of Materials Science and Engineering, Zhejiang University, 310058, Zhejiang, China.
³ UQ Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia.
⁴ School of the Environment, Nanjing University, 210023, Nanjing, China.
⁵ Monash Centre for Electron Microscopy, Monash University, Clayton, VIC, 3800, Australia.
⁶ CSIRO Manufacturing, Private Bag 10, Clayton South, 3169, Australia.
⁷ Australian Synchrotron, ANSTO, Clayton, VIC, 3168, Australia. qinfeng@ansto.gov.au.
⁸ Department of Chemical and Biological Engineering, Monash University, Clayton, VIC, 3800, Australia. xiwang.zhang@uq.edu.au.
⁹ UQ Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia. xiwang.zhang@uq.edu.au.

Abstract

Covalent modification is commonly used to tune the channel size and functionality of 2D membranes. However, common synthesis strategies used to produce such modifications are known to disrupt the structure of the membranes. Herein, we report less intrusive yet equally effective non-covalent modifications on Ti₃C₂T_x MXene membranes by a solvent treatment, where the channels are robustly decorated by protic solvents via hydrogen bond network. The densely functionalized (-O, -F, -OH) Ti₃C₂T_x channel allows multiple hydrogen bond establishment and its sub-1-nm size induces a nanoconfinement effect to greatly strengthen these interactions by maintaining solvent-MXene distance and solvent orientation. In sub-1-nm ion sieving and separation, as-decorated membranes exhibit stable ion rejection, and proton-cation (H⁺/Mⁿ⁺) selectivity that is up to 50 times and 30 times, respectively, higher than that of pristine membranes. It demonstrates the feasibility of non-covalent methods as a broad modification alternative for nanochannels integrated in energy-, resource- and environment-related applications.