Vacancy Functionalized MoS<sub>2</sub> Nanolaminated Membranes for Efficient Sieving in Forward Osmosis.

Ying, Ting; Onofrio, Nicolas; Mei, Liang; Peng, Huarong; Zhang, Zhen; Gu, Meng; Ma, Chen; Chen, Ye et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

2D transition-metal dichalcogenides (TMDs) based nanolaminates are promising candidates for water purification. However, fabricating nanochannels with tunable capillary widths remain a challenge. This study proposed a sulfur vacancy functionalization strategy for fabricating high performance nanolaminate membranes by grafting three kinds of thiol (S-H) containing molecules (Cysteine, 3-Mercapto-1,2-propanediol, 1-Propanethiol) on MoS<sub>2</sub> nanosheets, in which propanethiol functionalized MoS<sub>2</sub> membrane exhibited best salt rejection (99.3%) and water/salt selectivity (800 bar<sup>-1</sup>) in forward osmosis (draw solution: sucrose solution). It is found the capillary width increased from 0.2 Å in pristine MoS<sub>2</sub> to ≈5 Å in propanethiol functionalized MoS<sub>2</sub> membranes. Numerical simulations suggest that nanofluidic properties of the functionalized membranes are governed by the fundamental interaction between water and the corresponding S-H functional group, and the interlayer distance. Importantly, since the S-H containing molecules can repair MoS<sub>2</sub> nanosheets by fitting into the sulfur vacancies, the stability of the membranes is also improved with minimal swelling, which is promising for their practical applications.