Research Area

Advanced Charaterization

 

14

Computational Simultion

 

c1
c2
   

 

gra
Water in Graphene channel Density ~ 1.6 g/cm3
GO
Water in GO channel Density ~ 1.3 g/cm3

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Mass Transport in Confined 2D Nanochannel

The unique rhombus-shaped crystal structure formed between graphene sheets is very different from the typical hexagonal structure of ice crystals formed in bulk water. By combing QCM-D and Ellipsometry, we are able to measure the layer density as an important indicator of the water structure confined between two 2D nanosheets. The water molecules between GO sheets with a interlayer spacing of 0.8 nm still tended to form rhombus shaped units, similar to the structure between graphene sheets. However, the alignment of these rhombuses was obviously disturbed by the extruding oxygenated groups on GO, leading to a silightly lower density.Through MD simulation, we found the mobility of water molecules in the graphene channel was almost the same as that in bulk water, indicating that water did not experience any resistance from the graphene sheet during its transport, an observation consistent with the large slip length and theoretical high water transport rate in graphene channels. In comparison, the mobility of water molecules in the GO channel was much lower , indicating considerable resistance to water transport in the GO channel due to the existence of oxygenated functional groups.

 

Related Publication:

1. Zheng, S.; Tu, Q.; Wang, M.; Urban, J. J.; Mi, B., Correlating Interlayer Spacing and Separation Capability of Graphene Oxide Membranes in Organic Solvents. ACS Nano 2020.
2. Mi, B.; Zheng, S.; Tu, Q., 2D graphene oxide channel for water transport. Faraday Discuss. 2018, 209, 329-340.
3. Wang, Z.; Tu, Q.; Zheng, S.; Urban, J. J.; Li, S.; Mi, B., Understanding the aqueous stability and filtration capability of MoS2 membranes. Nano Lett. 2017, 17, 7289-7298.
3. Zheng, S.; Tu, Q.; Urban, J. J.; Li, S.; Mi, B., Swelling of graphene oxide membranes in aqueous solution: characterization of interlayer spacing and insight into water transport mechanisms. ACS Nano 2017, 11, 6440-6450.