title: Defective germanene as a high-efficiency helium separation membrane: a first-principles study.
abstract: Development of low energy cost membranes for separating helium from natural gas is highly desired. Using van der Waals-corrected first-principles density functional theory (DFT) calculations, we theoretically investigate the helium separation performance of divacancy-defective germanene. The 555 777 divacancy-defective germanene presents a 0.53 eV energy barrier for helium, which is slightly larger than the energy threshold value of gas molecule penetration of a membrane (0.5 eV). Thus, the 555 777 divacancy-defective germanene is difficult for helium to permeate, except under high temperature or pressure. However, the 585 divacancy-defective germanene presents a surmountable energy barrier (0.27 eV) for helium, and it shows extremely high helium selectivities relative to other studied gas molecules. Especially, the He/Ne selectivity can be as high as 1 × 104at room temperature. Together with the acceptable permeance for helium, the 585 divacancy-defective germanene can be used for helium separation with remarkably good performance.
authors.affiliation: State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong, People's Republic of China. College of Science, China University of Petroleum, Qingdao 266580, Shandong, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.forename: Xiao
authors.initials: X
authors.lastname: Chang
authors.forename: Daliang
authors.initials: D
authors.lastname: He
authors.forename: Qingzhong
authors.initials: Q
authors.lastname: Xue
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Li
authors.forename: Yakang
authors.initials: Y
authors.lastname: Jin
authors.forename: Haixia
authors.initials: H
authors.lastname: Zheng
authors.forename: Cuicui
authors.initials: C
authors.lastname: Ling