Theoretically designed two-dimensional γ-CO as an effective gas separation membrane for hydrogen purification.

A high-performance gas separation membrane for hydrogen (H) purification is still highly desirable for the sustainable development of our society. Based on the structure of γ-graphyne, we theoretically designed the two-dimensional nanomaterials γ-CX (X = O, S or Se) with intrinsic pores that may be suitable for gas separation. By first-principles calculations, we obtained the geometric structures of γ-CX, and confirmed that γ-CO and γ-CS are stable at room temperature. Due to the moderate size of the intrinsic pores, γ-CO exhibits a lower diffusion barrier and higher permeance for H than those of γ-CS. It is worth noting that at room temperature, the high selectivity (10) for separating H from a H/CH mixture by γ-CO shows great potential for H purification. Moreover, the classic molecular dynamics simulations at 300 K demonstrate that H can easily permeate through the intrinsic pores of γ-CO membranes with high permeability and selectivity, which supports our first-principles calculations.