Rational design of stable carbon nitride monolayer membranes for highly controllable CO capture and separation from CH and CH.

CO capture and separation from natural and fuel gas are important industrial issues that refer to the control of CO emissions and the purification of target gases. Here, a novel non-planar g-CN monolayer that could be synthesized the supramolecular self-assembly strategy was identified using DFT calculations. The cohesive energy, phonon spectrum, BOMD, and mechanical stability criteria confirm the stability of the g-CN monolayer. Our DFT calculations and MD simulations designate the g-CN monolayer to perform as a superior CO separation membrane from CH and CH gas owing to the high CO permeability and selectivity. Specifically, the CO permeability ranges from 1.21 × 10 to 1.53 × 10 GPU, while the selectivity of CO/CH and CO/CH is 3.03 × 10 and 3.10 × 10 at 300 K, respectively, much higher than the Robeson upper bound and most of the reported 2D membranes, and even at high temperatures, the g-CN monolayer-based CO separation membranes could operate with high performance. Further, at room temperature, the permeated CO gas can adsorb on the g-CN surface with moderate adsorption energy and high capacity. These results indicate that the g-CN membrane exhibits high performance for controlling CO capture and separation, which inevitably injects a new alternative of novel 2D membranes for CO separation and capture from CH and CH in light of further experimental and theoretical research.