title: Insight into the Nanoscale Mechanism of Rapid H2O Transport within a Graphene Oxide Membrane: Impact of Oxygen Functional Group Clustering.
abstract: 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.
authors.affiliation: State Key Laboratory of Offshore Oil Exploitation , Beijing 100027, China.|Institute of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) , Fuxue Road 18, Beijing 102249, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Ban
authors.affiliation: Institute of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) , Fuxue Road 18, Beijing 102249, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.affiliation: Institute of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) , Fuxue Road 18, Beijing 102249, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Offshore Oil Exploitation , Beijing 100027, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Jing
authors.affiliation: State Key Laboratory of Offshore Oil Exploitation , Beijing 100027, China.|State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) , Fuxue Road 18, Beijing 102249, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Liu
authors.affiliation: Institute of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing) , Fuxue Road 18, Beijing 102249, China.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Zhou
keywords: adsorption; diffusion; gas permeation; graphene; intercalation; molecular simulation; surface chemistry