Insight into the Nanoscale Mechanism of Rapid H2O Transport within a Graphene Oxide Membrane: Impact of Oxygen Functional Group Clustering

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• 作者：Shuai Ban ; Jing Xie ; Yajun Wang ; Bo Jing ; Bei Liu ; Hongjun Zhou
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：8
• 期：1
• 页码：321-332
• 全文大小：945K
• ISSN：1944-8252

文摘

Realistic models of graphene oxide membranes were developed and validated to interpret the exceptional water permeation in association with X-ray photoelectron spectroscopy, thermogravimetric and differential scanning calorimetry analysis, and dynamic vapor sorption measurements. With respect to the GO oxidization level, surface distributions of functionalized domains were analyzed in line with TEM observations, and 3 types of interlayer domains in slit pores of GO membranes were identified. The hydrophilicity degrees of as-defined domains strongly influence their H₂O uptake capacities. Calculated sorption enthalpies and isotherms are in good agreement with experimental data, and the results indicate the dominant role of dipole interactions. GO expansion shows a transition from the interstratification of an H₂O monolayer to the accumulation of H₂O multilayers at an interlayer distance of 0.8 nm. The evolution of both hydrogen bonds and H₂O diffusivities suggests the existence of three types of H₂O species with different binding states and molecular mobilities. The computed H₂O permeability on the basis of sorption-diffusion theory supports the exceptional H₂O transport capacity in GO membranes.