A remarkable two-dimensional membrane for multifunctional gas separation: halogenated metal-free fused-ring polyphthalocyanine

We theoretically explore the structural and mechanical properties of metal-free fused-ring polyphthalocyanine (H2PPc) and halogenated H 2 PPc (F-H 2 PPc and Cl-H 2 PPc) membranes, and the energy profiles for gaseous H 2 , CO, CH 4 , CO 2 and N 2 molecules adsorbing on and passing through these monolayers. Importantly, we reconsider in depth the values of the parameters in the definition of permeance, and corroborate the validity of the model from first-principles theory with the results of H 2 diffusion from classic molecular dynamics simulations. With well-defined nanosized pores, halogenated H 2 PPc monolayers turn out to be multifunctional gas separation membranes, i.e. F-H2PPc for H 2 /CO, H 2 /CH 4 , CO 2 /N 2 , CO 2 /CH 4 , CO/CH 4 and N 2 /CH 4 separation as well as Cl-H 2 PPc for H 2 /CO, H 2 /CH 4 and H 2 /CO 2 separation, which should be of great potential in energy and environmental fields.