Highly Efficient Quantum Sieving in Porous Graphene-like Carbon Nitride for Light Isotopes Separation

Abstract

Light isotopes separation, such as 3He/4He, H2/D2, H2/T2, etc., is crucial for various advanced technologies including isotope labeling, nuclear weapons, cryogenics and power generation. However, their nearly identical chemical properties made the separation challenging. The low productivity of the present isotopes separation approaches hinders the relevant applications. An efficient membrane with high performance for isotopes separation is quite appealing. Based on first-principles calculations, we theoretically demonstrated that highly efficient light isotopes separation, such as 3He/4He, can be reached in a porous graphene-like carbon nitride material via quantum sieving effect. Under moderate tensile strain, the quantum sieving of the carbon nitride membrane can be effectively tuned in a continuous way, leading to a temperature window with high 3He/4He selectivity and permeance acceptable for efficient isotopes harvest in industrial application. This mechanism also holds for separation of other light isotopes, such as H2/D2, H2/T2. Such tunable quantum sieving opens a promising avenue for light isotopes separation for industrial application.

Efficient hydrogen isotopologues separation through a tunable potential barrier: The case of a C2N membrane

“…2), the D 2 permeance Q ( D 2 ) and the kinetic selectivity S ( D 2 / H 2 ) 19, 21, 33, 34 . Unlike the case of helium isotopes 21, 33 , the ZPE correction leads to a lower barrier for D 2 than that for H 2 , and thus the larger quantum tunneling probability of D 2 .

Figure 2Quantum tunneling probability t ( E ) of hydrogen passing through the pore of C 2 N- h 2D membrane as a function of kinetic energy under different strains. The solid curves represent the quantum-mechanical transmission of H 2 and the dashed curves represents that of D 2 , respectively.

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“…3 He) is more inclined to transmit through the membranes 18–20 . In these systems, the interaction between the membrane and the guest isotopes can be tuned by applying tensile strain which modifies the pore size of the membrane, and highly efficient isotopes separation with optimized selectivity and permeance can be obtained 21 . It is noteworthy that the zero-point-energy (ZPE) of hydrogen in confined systems would affect the energy barrier on the diffusion pathway 12 .…”

Enhanced Photocatalytic Water Splitting in a C2N Monolayer by C‐Site Isoelectronic Substitution

“…Theoretical reports have shown that the magnetism of the C 2 N monolayers can be tuned by transition‐metal embedding into the cavity of the porous C 2 N monolayer and carrier doping . Earlier reports have shown that the C 2 N monolayer is an excellent candidate for gas separation because of its uniformly distributed subnanometer pores with designable pore sizes . Furthermore, C 2 N has been employed for widespread applications such as single‐atom catalysts, hydrogen evolution reactions (HER), oxygen evolution reaction (OER) catalysts, and water desalination …”

Carbon-rich carbon nitride monolayers with Dirac cones: Dumbbell C4N

“…Among these, graphitic carbon nitride (g-C 3 N 4 ) has been studied for a long time [22] and it can be used in many energy applications, such as hydrogen generation [23], efficient energy storage [24], and photocatalytic degradation of pollutants [25]. Nanoporous carbon nitride materials, such as the C 2 N monolayer [26], can be applied in gas separation [27][28][29] or water desalination [30]. The carbon nitride materials not only have a huge potential in applications but also exhibit many interesting physical effects, including QSH [31], quantum anomalous Hall (QAH) [32,33], and spin-polarization [34,35] effects.…”