Excellent membranes for hydrogen purification: Dumbbell-shaped porous γ-graphynes. (23rd February 2017)

• Record Type: Journal Article
• Authors: Sang, Pengpeng; Zhao, Lianming; Xu, Jing; Shi, Zemin; Guo, Sheng; Yu, Yanchen; Zhu, Houyu; Yan, Zifeng; Guo, Wenyue
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 8(2017)
• Page Start: 5168
• Page End: 5176
• Publication Date: 2017-02-23
• Subjects: H2 purification -- γ-graphyne membrane -- Density functional theory -- Molecular dynamic simulation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.11.158
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Two dumbbell-shaped porous γ-graphynes were designed by substituting one-third acetylenic linkages with heteroatoms nitrogen and hydrogen named γ-GYN and γ-GYH, respectively. The calculated cohesive energies and phonon dispersion spectra indicate the possibility to realize the new membranes in experiments. The separation performance of the designed monolayers for H2 from H2 O, CO2, N2, CO, and CH4 was investigated using both first-principle density functional theory (DFT) and molecular dynamic (MD) simulations. The DFT calculations suggest the designed membranes are excellent in H2 separation because of the super high selectivities of H2 over other gases H2 O, CO2, N2, CO, and CH4 (>10 10, 10 13, 10 21, 10 18, and 10 46, respectively, at room temperature) together with the high/extremely low permeances for H2 /other gases, e.g., reaching the industrial standard at 400 K (γ-GYN) and 425 K (γ-GYH)/lower than the industrial limit by 3–22 orders even at 600 K. The MD simulations indicates that only H2 in the gas mixture containing H2, H2 O, CO2, N2, CO, and CH4 can penetrate across the membranes even at the temperature of 600 K and γ-GYN is more favorable for H2 penetration. All these results indicate both the designed membranes, especially γ-GYN, are excellent candidates for H2 purification from gas mixtures. Graphical abstract: Dumbbell-shaped porous γ-graphynes γ-GYN and γ-GYH can effectively separate H2 from H2 O, CO2, N2, CO, and CH4 . Highlights: Two dumbbell-shaped porous γ-graphyne membranes were designed for H2 purification. The H2 separation performance of the membranes were studied using both DFT and MD simulations. Both the graphyne-like membranes can separate H2 with excellent selectivity and acceptable permeance.