High-efficient hydrogen purification through two-dimensional CrI3 membrane via a first-principles calculation

Abstract Porous two-dimensional materials are potential candidates for the realization of gas separation, which are crucial for developing clean energy sources. Here, we found that CrI3 monolayer which has uniform nanopores around 2.9 A in intrinsic structures can simultaneously fulfill the requirements of both high permeability and high selectivity. Our results show that the diffusion energy barriers of H2 and impurity gases (N2, CO, CO2, H2O and CH4) passing through the nanopores of CrI3 monolayer are 0.27 eV, 1.49 eV, 1.31 eV, 1.54 eV, 0.87 eV and 3.88 eV, respectively, which indicates that these impurity gases hardly pass through the CrI3 monolayer and H2 can be effectively separated from the gases mixture. Also, at the temperature of 300 K, the permeability of H2 (1 × 10−5 mol·m−2·s−1·pa−1) is significantly larger than the minimum acceptable permeability for industry (6.7 × 10−9 mol·m−2·s−1·pa−1). Thus, the CrI3 monolayer is a promised candidate of the hydrogen purification for the future applications.